StumbleUpon’s search feature has always been a bit lacking, the results page leaving you with a seemingly unorganized list of relative content (the results aren’t in order of popularity or by date of submission). StumbleUpon’s search is further handicapped by it’s inability to search by domain. StumbleUpon offers directions for searching by domain, but I’ve rarely managed to get any results from domains other than the likes of CNN.com.
Those shortcomings aside, StumbleUpon seems to be making more of an effort at getting their users to utilize search with the inclusion of a prominent suggested search box on every user’s home page (it’s also included in the Chrome/Web and Firefox versions of their toolbar).
The inability to search through a topic, rather than “Stumble Through” a topic, has always been one of StumbleUpon’s glaring weaknesses. This is an obvious sign that StumbleUpon agrees. Now if only they can perfect the domain search.