This year, Google got an early and unexpected holiday gift from Microsoft. Whether it was the Christmas spirit or merely a glitch in the Redmond company's search engine indexing process, the result has been the same: Live Search, a direct Google competitor, served users Google ads. Homer Simpson's D'oh! trademark onomatopoeia, repeated in the situation by Nathan Buggia, Live Search Webmaster Center, managed to fairly describe the Live Search slip up. The problem permitted Live Search to return a consistent amount of Google advertisements as results of the users' queries. The issue was only temporary and Microsoft identified the cause, resolving the matter, and taking back Google's gift.

"The issue stems from the way Live Search handles content disallowed by the Robots.txt file. We regularly check the robots.txt file of a site to ensure that we don't index and cache pages excluded by the webmaster. However, if we do find a link elsewhere on the web pointing to a page excluded by the robots.txt file, we may include the link and the anchor text in our index if we think it might be valuable to our users. Yesterday we accidentally began including the links from the ads of Google AdSense customers. The issue has been fixed, and you should see the results disappear from our search results over the next couple days", Buggia explained.

An estimated 4 million Google AdSense ads were indexed by Live Search. Microsoft failed to reveal the proportions of the problem itself, as it moved fast to scrap all traces of Google ads being served to users via Live Search. At this point in time, entering the "site:www.google.com/pagead" query into Live Search will return absolutely no results. This is not the first time that Live Search's indexing process has been acting up. In mid December, Microsoft announced that it had optimized its crawler in order to better handle cloaking, a search engine optimization technique.