An observation about Twitter (and Google)
Here is something I've noticed lately: when I want to look for traces of some recent or just-breaking piece of news, such as IPSCa's utter failure or important potential Solaris licensing changes, I no longer bother trying Google or other general search engines; instead, I go to Twitter and search there. And it works. There's a certain amount of noise in the result but also a lot of signal, more than I could easily get otherwise.
Partly I think that this is because all of the existing blog search engines basically suck; they are some combination of incomplete (some to the point of being jokes), unusable, or overrun by spam. I was about to say that general search engines are mostly useless, since I specifically want recent updates, but actually at least Google now has options for that; sadly, a test search suggests that this is less than entirely useful for anything except very specific terms when combined with 'order by date'.
In large part, though, it is because the sort of activity that happens on Twitter and how it's organized fits well with what I want to learn, provided that it's something people tweet about. Twitter searching is inherently newest-first (at least right now), and it (mostly) consists only of people actively writing about things, with little or no automated tweets or spam. It has drawbacks, such as people don't necessarily link to primary sources of information, but right now they're small compared to Twitter's advantages. (And just knowing that people are talking about something can be useful information.)
I'm not certain that a good blog search engine could overcome Twitter's advantages. In fact, I sort of think that a good blog search engine these days would have to search Twitter too, because it seems that Twitter is increasingly where quick link-blogging goes and for my purposes I need to capture both people writing about the subject and people linking to stuff about the subject.
I'm sure that all of this says something about how information is shifting around on the Internet, but I'm not sure exactly what it says. (To the extent that it de-emphasizes blogs, I'm vaguely sad; I like blogs. But I think it's undeniable that common implementations are a bit heavyweight for short things and just noting links.)