This is an experiment. I uploaded my Google [RSS] Reader OPML to Google Co-op. It seems to do much the same that
lijit does for
me.

Admittedly, there is a bit of self-referential (how unusual!) circularity here. While I don't think this is a tool to expand my worldview, it is an excellent card catalog for my existing perspective (as determined by my preferred information gatekeepers listed in my OPML). With
jonswift (gets all his "news from Fox News, Rush Limbaugh and Jay Leno monologues"),
chemgasm (libertarian doper),
fafblog (hysterically
erudite), and
Brad DeLong ("fair and balanced almost every day") in there, I am assured of great results when trying to identify, say,
the stupidest man alive or the
link between recreational pharmaceuticals (esp hallucinogens such as LSD) and the rather staid policy wonks at the
Cato Institute.
The only problem I can see is that because the OPML is output to a file as opposed to a URL (cf bloglines, newsgator) I will need to go through the process again if I want the search engine to reflect my evolving interests as embedded in my OPML. I've only just discovered by doing a search that Time Magazine resides in my OPML, but because I have it tagged with some sort of priority indicator that means I would not see a post under normal circumstances I've long forgotten it's there. Obviously, having dynamically updating OPML at a URL is a feature that will be offered soon, but I think Google is remiss in not having addressed this already.
reference:
Google Operating System