Google AdWords now personalized

Hat Tip: Found via Greg Linden's blog: Google AdWords now personalized. Below are my thoughts and questions:

Google is now reaching back into your previous search history and presumably choosing a better previous search if the current one is not sufficiently monetizable.

Questions:

• Is the goal of Google to increase the fill-rate of ads or to show more valuable ads in general?
  
• What criteria is used to reach back into a user's history? Boolean commercial/non-commercial then select last commercial search versus choosing based upon some selection algorithm from the last N searches (see previous point).
• Will the reach-back cross a topic boundary or is it only to enhance context for an ambiguous search?
  
• What effect will this have on the Google Keyword Tool that helps advertisers forecast demand and price for a keyword? The volume numbers must now be adjusted by the amount of time the impressions are shifted to alternate keywords.
• How much will this starve the long-tail of searches? Depending on the aggressiveness of the selection then long-tail searches may suffer a decrease in volume for adwords.
  

Even the most modest change of merely using recent previous searches only 'about' the current search to augment the adwords auction query should have a dramatic effect on the auction process. By definition it expands the number of bidders for a particular query. It may also curtail the effectiveness of arbitrage done by some adwords buyers who buy ambiguous lower value keywords as proxies for high value ones due to user sessions with query reformulations. Why? It should have the effect of driving up prices for the penny keywords if they are sufficiently related to high value keywords.

It will be interesting to watch what happens. This is likely not a non-trivial change in the keyword market.

Posted via email from nealrichter's posterous

A Subtle Art

I loved this quote from a NYT Blog post:

"By attracting a commanding share of the search advertising activity, Google also has the best data with which to create equations that maximize the money it makes from each search. It turns out that picking which ad to display when is a subtle art that can have a great effect."

I've been working on effectively harvesting and choosing keywords to best power and adnetworks like Google/Yahoo/MSN. I believe it's much harder than simply producing good search results. Search results are targeted at people explicitly looking for information, so in that sense it's like an auto-generated yellowpages entry, people want to click on something. The adverts on these pages benefit from the explicit nature of the search.

How do you do the same for display advertising on the rest of the non-SERP pages of the web? You get one shot at providing value, a bit like trying to hit the green from the rough and through a stand of trees. A subtle art indeed, and great fun to work on.

Using human relevance judgements in search and advertising

This is old news on a couple of dimensions. Read Write Web had a post on how Google uses human relevance studies to help judge/QA their search results. This resulted from an interview that Peter Norvig gave to MIT Technology Review and caused some commenting in the blogosphere (NewYorkTimes Tech Blog, Goolge Blogoscoped). Old news on old news.

We now know that both Yahoo and Microsoft are using (to some degree) human studies to evaluate computational advertising algorithms (see this and this). Evaluating the correlation of what informational item an algorithm predicts, vs what humans think, is relevant to a context is the performance metric of your algorithm.

Question: When will TREC have a computational advertising contest?

Text Summarization and Advertising

Recently read another CompAdvert paper (CIKM'07) from the Yahoo group, Just-in-Time Contextual Advertising. They describe a system where the current page is scraped on-line via a javascript tag, summarized and then that summary is passed to servers to match with Ad listings. Interesting points are:

• 5% of page text carefully chosen can yield 97+% of full-text advert matching relevance
• Best parts of the document are URL, referring URL, title, Meta and headings.
• Adding in a classification against a topical taxonomy adds to the accuracy of the ad matches.
  
• They judged the ad matching relevance against human judgments of ad to page relevance.

I found these papers within the last few months as OthersOnline focused on behavioral based advertising. In many ways their finding are interesting, affirming and unsurprising. Interesting in that they are pushing the state of the art in advert matching, and affirming in that we @ OO are on the right track. Unsurprising in that using the document-fields about is the classic approach to indexing webpages and documents.
Of course internet search engines used this for years (it defines the SEO industry's eco-system), and the old/retired open source engine HtDig has had special treatment of those fields since the late 90s. The difference now is the direction, the documents are the "query" and the hits are the ads. Best part about the method is that it's cheap... javascript + the browser becomes your distributed spider and summarizer of the web.
I do love finding these papers.. we just don't have the time or resources to have a study like this and confirm the approach with a paid human factors study. Just go forward on gut educated feel day to day and the human measure is if we get clicks on the ads.
This approach is similar to the one we outlined and implemented before finding this paper. The difference is what we do with the resulting "query", using the signal to learn a predictive interest model of users.
Still no mention of any relative treatment of words within the same field... one would assume this would move the needle on relevance as well.
I still believe that this type of summarization approach can be used to make an implicit page tagger and social recommender like del.icio.us ... if you can filter the summary based upon some knowledge of the users real (as opposed to statistical) interests. Key route to auto-personalization of the web.

Semantic Features for Contextual Advertising

Andrei Broder's group at Yahoo! Research has a focus on Computational Advertising. At SIGIR 2007 they released a paper on using Semantic Taxonomy to do contextual matching for advertising. This is a similar problem to the previous post about MS Research, deriving lists of keywords from a document to use as queries to an advertising system. Unlike the MS Research paper, Yahoo has built a large taxonomy of "commercial interest queries" with 6000 nodes and approx 100 items attached to each node.

The essential approach is to classify a document into the taxonomy as well as all of the ads and match ads to documents on the basis of topical distance. The distance score is combined with a more standard IR type approach forming a combined score. The top-k matching ads ordered by lowest distance are the ads displayed the page.

The TaxScore() function is fairly interesting, it attempts to generalize the given term within the taxonomy. It seems that this type of approach could work well with using WordNet's Hypernyms in a more regular IR/Search setting.

I have to read it again more carefully to see if I missed it, however I did not see anywhere in the formulas using any weighting of a keyword's bid value (or advert count). Maybe this was omitted for trade secrecy?? .. it seems obvious that it should be used to some degree to maximize $$ yield or eCPM of clicked ads. The idea is not to let it affect the matching of the ads to keywords, just the final rank order to some degree.

In my own experiments @ OO, using some proxy for bid value seems to increase eCPM. The biggest challenge is getting comprehensive data for your dictionary if you are not Google, Yahoo or MS.

Postscript:
I have it confirmed from two independent sources (current and ex Y!ers) that Yahoo is working in a new Content Match codebase as the old version didn't work. Hard to say what status Broder's above technique is in (production usage or internal testing).. or if it was part of the old system?

Scraping Documents for Advertising Keywords

Lately I've been working on extracting keywords from text that would be associated with good keyword advertising performance. This is fairly related to the 'text summarization' problem, yet that usually works towards a goal of readable summaries of documents. This is a simpler problem as I don't want to build readable summaries.

'Finding Advertising Keywords on Web Pages' from MS Research (Yih, Goodman, and Carvalho) was interesting reading. To boil it down to its essence, the authors used a collection of standard text indexing and NLP techniques and datasets to derive 'features' from the documents, then used a feature-selection method to decide what features were best in deciding good advertising keywords in a document. They judged the algorithms against a human generated set of advertising keywords associated with a group of web pages. Their 'annotators' read the documents then chose prominent words from the document to use as viable keyword advertising inputs.

Note that this is not an attempt to do topic classification, where you could produce a keyword describing a document that did not exist in the document.. for example labeling a news article about the Dallas Cowboys with 'sports' or 'event tickets' if those labels did not exist in the article.

Interestingly the algorithm learned that the most important features predicting a word's advertising viability was the query frequency in MSN Live Search (a dead obvious conclusion now supported by experiments), and the TF-IDF metric. Other features like capitalization, link text, phrase & sentence length and title/headings words were not as valuable alone.. yet (unsurprisingly) the best system used nearly all features. The shocker was that the part-of-speech information was best left unused.

I emailed the lead author and learned that the MS lawyers killed the idea of releasing the list of labeled URLs.

Post Script: The second author is Joshua Goodman, who had a hilarious exchange with some authors from La Sapienza University in Rome. They wrote a 2002 Physical Review Letters paper on using gzip for analyzing the similarity of human languages. Goodman responded with this critique, causing the original authors to respond with this response. Looks like there are other follow ups by third-parties. The mark of an effective paper is that it is talked about and remembered.

Refocusing of Others Online to Behavioral Targeting and Computational Advertising

On the work/professional front Others Online is going into a bit of a transformation.

A rethinking exercise demonstrated that what we do best was connect people with content based upon implicit attention streams (this can be anything, click streams, blog posts, twitter, searches). That content was other people (social referrals), content (web pages & blogs) and ads.

Optimizing the process of selecting ads for individual people/groups and context rather than broad categories is what we'll focus on for a while, particularly me as concentrate on being the computational advertising guy at OO.

As for the social networking part of the software, we're refocusing on adding value to existing community and topical sites and other like groups that tend to connect people around a specific topic or geography.

Personally I think the refocusing on computational advertising and targeting is a great choice. When was the last time a web advertisement was really relevant to you? Do you really want to see noisy advertisements for mortgage refinancing and Viagra-like products? The key to all of this is to be socially responsible and give users complete control so that we don't fall into the Facebook-Beacon backlash.

Well, that and some clever algorithms to do the learning.