StumbleUpon is a webservice which allows users to surf interesting sites based on links it feeds users via a browser toolbar. While this is clearly not the same exercise as searching for websites based on content, it does provide users with a way to find relevant information about certain channels which are popular within some social context… and in many instances when users don’t quite know what they want, this can be very useful.

Many times, search can be so generalized that even a small amount of social context (friend or user recommendation) can improve content search drastically.  Ebay must have thought along these lines because earlier today it announced that it would acquire StumbleUpon (for ~$40 mn).

Ebay is also not alone in acknowledging this value. After Ebay’s announcement today, Google announced a new feature in their toolbar with similar functionality in that it helps people to find websites they may find interesting based on prior searches (loose direction). While this does not explicitly use a social model, the algorithms which power this feature are probably trained on the logs of the searches of similar users. In addition to the feature itself, this is clearly a signal to StumbleUpon acknowledging the potential importance of this type of context.