Colin's pages on CUPS printing and TalAggregator made the top hits, which is quite reasonable. The first especially is quite widely linked to. By the end of the first page, the Digital Medievalist had shown up, because she links to my Medievalist list. By the second page, my regular webpages had shown up. By the fifth page, spam referrers to my weblog had shown up (you know, sites that warehouse links to webpages of all sorts in an effort to up their search engine ranking). By page 18, I'd run out of pages to look through, and Livejournal hadn't shown up at all in its own right - only as something to be linked to.
Weblogs are difficult things for search engines to deal with. Updating frequently, having lots of content, and being linked to are all flags for a webpage's important. But weblogs are easily abused as well, set up by page rank manipulators, for example. And then there's comment spam, which is what Google (and Livejournal and all sorts of other major sites) are trying to work around with the new rel="nofollow" flag. (Although if LJ is disabling anonymous links, then what do they mean by "unknown links" in the news post?)
But even if weblogs are easily abused, that's a challenge that MSN needs to take on, because there are plenty of reputable sites inamongst them. And failing to index a site like LJ isn't a competent solution.