One of the hot areas in search is personalization. Google recognizes that personalization is a way to offer people better search results. How this works has a big impact on SEO, and I had the opportunity arise to speak with Jack Menzel and jumped at it. Here are some of the key points from the discussion:
- People confuse context with personalization, and these are different things. Context includes factors such as language, location, and time of year.
- (Jack:) “A lot of people assume personalization is amazingly pervasive”. In fact only small changes are made to a results page based on personalization. Google recognizes for diverse query results.
- Past query history is used for personalization. If you search for “rome”, and then “hotels”, some of the results will be for hotels in Rome.
- Past click through history is a factor. If you show a clear preference for one site by clicking on it in the results, then it may be moved up in the results for you.
- The recommendations of friends are used in personalization.
- Google will look at your friend's profile to see what networks they have included there, and then see what they recommend on those sites.
- (Jack): “When people are signed out, their search results are personalized based on past search information linked to their browser for up to 180 days using an anonymous cookie”.
- Appending &pws=0 to the end of a URL does work, but it only removes personalization, it does not remove context (language, location, time of year).
- There are ways to turn off all personalized results. Google's position is that user's own their data. However, context will still be taken into account.
Eric Enge: Sometimes people confuse the notion of context with personalization, right?
If I respond to your query in your language that is really about context, not personalization.
Jack Menzel: That's right. Sometimes results that are really a result of context get misinterpreted by people as personalization. If I respond to your query in your language that is really about context, not personalization. Personalization is more about recognizing that I like Dominion the card game and you really like Dominion the power company, and someone else really likes a videogame called Dominion. Imagine you turned off personalization, and suddenly Google was responding to all of your queries in the wrong language, you would be like “oh come on”.
Eric Enge: Another example would be that you are in the US and Halloween is in the near future.
Jack Menzel: Correct, right before thanksgiving there are a lot of searches about turkeys, and it often means people want turkey recipes.
Eric Enge: What are some of the other kinds of things that fit into the definition of context?
Jack Menzel: Let's use a conversation based example. If we are both in Mountain View and I am talking to you about catching a bus, I don't have to remind you that I am talking about bus in Mountain View, as opposed to one in Austin, Texas.
We take into account geography, language, and seasonality to a certain extent.
We take into account geography, language, and seasonality to a certain extent. The context of the previous queries is kind of on the borderline of what is personal and what isn't.
Eric Enge: For example, if a person's previous query was “Rome”, and then they search on “hotel”, there is going to be a tendency to show hotels in Rome.
Search results 3 to 5 for “hotels” when the prior search was for “rome”
A lot of people assume that personalization is still amazingly pervasive.
Jack Menzel: Your example may work, but I would have to check to make sure. A lot of people assume that personalization is still amazingly pervasive. We believe we are able to do some really useful things with personalization, but we may not get all of these things exactly right.
Eric Enge: What are some good examples of personalization that you think are handled well at this point?
We refer to this as “pattern” analysis, and it is based on recognizing preferences.
Jack Menzel: My interest in the card game Dominion is an example of this. I really don't care about the power company at all. We refer to this as “pattern” analysis, and it is based on recognizing preferences. That's an example of understanding the kind of topics that I am more interested in. Also, I do a lot of web programming, so when I talk about vectors, it will mean something very different than when a doctor talks about vectors.
Search results for “dominion” for someone with no related search history
We recognize patterns very well. If I keep going to visit my favorite scrabble dictionary over and over again I will see that the site that I tend to prefer will end up being boosted in the ranking because it makes it easier and faster for me. Pattern recognition is important because there is so much ambiguity in language.
Eric Enge: Jaguar, is my favorite example because you have the guitar, the operating system, the animal, and the football team. I would probably get the football team a lot, because I am a football fan.
Jack Menzel: Right, exactly. If you tend to gravitate towards football sites as opposed to operating system sites then you would end up getting that.
Eric Enge: How about social data?
We leverage social data pretty well. If your friend likes a restaurant, they can indicate it in a way that we (Google) can see that (such as a +1).
Jack Menzel: We leverage social data pretty well. If your friend likes a restaurant, they can indicate it in a way that we (Google) can see that (such as a +1). When you’re searching for a restaurant and you’re signed in, we may well boost that restaurant's site in the rankings for you as well. We will also annotate the results, so that you can clearly see that this is content from your friend.
Search results for “reconsideration requests” with personalization on and off
Eric Enge: How do you determine what social properties people are on?
Jack Menzel: We look at people's profiles and see what social profiles they have included in there, and we can then see what they share on those sites, provided that the information is public.
Eric Enge: If it's not connected through your profile and your friend's profiles then you are not going to use it to personalize results.
Jack Menzel: That's correct.
Eric Enge: Do you need to be logged in to get personalized results?
We do a certain amount of personalization for people who are not logged in.
Jack Menzel: Being logged in is the best way to get personalized results. We do a certain amount of personalization for people who are not logged in.
Eric Enge: Is that cookie based?
Jack Menzel: Yes, we do some cookie-based personalization, which applies to search sequences where the subsequent searches feel more like a conversation. If you take that away from people it tends to be kind of frustrating. And so, there are certain parts of personalization that we still do.
Eric Enge: What kinds of personalization do you still do when people are logged out?
Jack Menzel: When people are signed out, their search results are personalized based on past search information linked to their browser for up to 180 days using an anonymous cookie. But if you're signed out, we have much less data to personalize your results with than if you're signed in.
Eric Enge: For example, you wouldn't be able to use the social information.
Jack Menzel: That's right. We have no idea about any of the social information. We only have a very limited knowledge of what your previous actions may have been, but we try to save you from having to repeat every detail in every query. But, it's not as personalized as a signed in version.
Eric Enge: There aren't any issues in this approach with shared IP addresses, because you are dealing either with people who are logged in or have a cookie.
Jack Menzel: That's right. However, you can still run into the problem of shared computers where things get a little muddled. For example, if you are at an internet café and you are just doing a couple of searches to find out where the newest movie can be found. In general though, we don't tend to have problems at the IP level because the system is based on cookies or being logged in.
Eric Enge: In the case of my machine at home, my 16-year-old daughter can come in and do some searches on it. That's pretty hard to disambiguate I suspect.
Jack Menzel: That is very hard to do.
Eric Enge: In that environment if she does log me out and log herself in, is there a cookie involved at that point or does it just immediately switch to personalizing for her?
Jack Menzel: Yes. It doesn't have much do with your cookie. It's completely associated with your sign in.
Eric Enge: Does appending &pws=0 to the end of a search result URL still turn off personalization as it used to?
Procedure for turning off personalization with &pws=0
It (&pws=0) turns off “personalization”. However it isn't really useful because people assume that it then will show them what everyone else sees. That simply isn't the case.
Jack Menzel: Yes it does work. It turns off “personalization”. However it isn't really useful because people assume that it then will show them what everyone else sees. That simply isn't the case. There are a whole lot of contextual factors that make everyone's results most relevant to them. This takes most of the wind out the sails of these types of analysis.
If personalization is turned off, we will still take a lot of context into account, including things such as location, language, and time of year. Of course, you can also get rid of context most of the time by getting more specific about your query. For example, if you live in the US but want to learn about the UK tax code, you would search on something like “UK tax code” to make that clear. Or you can conduct the search at www.google.co.uk instead too.
Eric Enge: When you use search history I assume you need to accumulate a certain enough data to achieve significance involved?
Jack Menzel: Yes, of course. We don't want you to have done one query out of curiosity, and then suddenly decide that you are really into macramé. We are looking for a meaningful pattern.
Eric Enge: The other area that I think people get concerned about is the potential the loss of serendipity, but it's not like you remap the entire results page around this.
Jack Menzel: It does make me kind of sad that when we talk about serendipity and search engines that we don't point out the fact that search engines are the most amazing tool when it comes to discovering new things.
We have lowered the barrier and made it possible to research anything you could possibly imagine in the time it takes for you to type a query and hit enter. A fraction of a second later you've got some of the best results in the world for you to dig through. It makes it so easy. If we personalize the results page to the extent that we were only showing results tailored for you, that would be a bug for us. We would never want to do that.
So when we personalize a page the changes are pretty small, and we want to leave the other results untouched by personalization.
We try to give people the most usable page, but on the other hand we also try to give people the most relevant page to them. So when we personalize a page the changes are pretty small, and we want to leave the other results untouched by personalization. Using your interest in football as an example, even though you love football, some of the time you may actually want information on the animal, the guitar, or the OS instead.
Eric Enge: There is this long standing notion that's been out there called query deserves diversity.
Jack Menzel: That's right.
Eric Enge: This is obviously something that Google has known for quite some time because it's many years since I first heard about query deserves diversity. Since you are trying to get as close to satisfying a 100% of the people 100% of the time over-personalizing would fail to do that.
Jack Menzel: That's right. We really do want to show people a good representation of what the most relevant results would be, and people like that.
Eric Enge: Can you also discuss your approach to transparency and control?
Our position is that this is your data and you have control over your data.
Jack Menzel: We think is really important in any conversation about personalization. Our position is that this is your data and you have control over your data. You do have control over your web history, and you have control over how your browser manages cookies. We take the privacy of people's data, and how we manage data, and how people have control over that data really seriously.
At the feature-level we try to make it very transparent to people what it is we are doing. We really are trying our best to be the industry leaders in how people have control over the data.
Eric Enge: Are there any aspects of personalization that people can't turn off?
Jack Menzel: There are ways to turn all aspects of personalization off. If you do want to really not have your queries tracked between, or if you don't want to have your content tailored to you in any way, shape, or form, you can set your browser to not accept cookies, and then we think you are a brand new person every time. Also, bear in mind that we will still take into account context, such as the right language for your results, your location, and the time of year.
Eric Enge: Thanks Jack!
Jack Menzel is a Product Management Director for Google Search. Jack leads the teams developing new technologies used for personalization, question answering, web page summarization, and image search. Prior to joining Google Jack worked as a Program Manager at Microsoft. Jack holds a MS in Computer Science from the University of Washington as well as an BS in Computer Science and Mathematical Economics from Brown University.
Other Recent Interviews
Google's Peter Norvig, October 17, 2011
Google's Mayuresh Saoji, October 10, 2011
Google's Frederick Vallaeys, September 29, 2011
Bing's Ping Jen, September 28, 2011
Bing's Duane Forrester, September 6, 2011
Danny Sullivan, August 8, 2011
Bruce Clay, August 1, 2011
Google's Tiffany Oberoi, July 27, 2011
Vanessa Fox, July 12, 2011
Jim Sterne, July 5, 2011
Stephan Spencer, June 20, 2011
SEOmoz' Rand Fishkin, May 23, 2011
Bing's Stefan Weitz, May 16, 2011
Bing's Mikko Ollila, June 27, 2010
Yahoo's Shashi Seth, June 20, 2010
Google's Carter Maslan, May 6, 2010
Google's Frederick Vallaeys, April 27, 2010
Matt Cutts, March 14, 2010