The combination of blogs and aggregation is so powerful not justbecause these are complementary technologies in the obvious sense, butbecause they promote a 'virtuous cycle' that promotes the creationa andtransformation of information. Of course this cycle isnothing new -- it's been around since forever, through the media ofbooks, libraries, universities, newspapers, et cetera -- but theblog/aggregation combination vastly speeds up the process and reducesthe transaction cost to effectively nothing. Which makes the Long Tail of the information economy accessible.
That's why the announcement of My MSN RSS aggregation with feed search is interesting; a My MSN aggregator, plus MSN Spacesmeans Microsoft can leverage both sides. So they could make itvery easy, for example, to subscribe to the RSS feeds for Spaces ownedby people who comment on your blog. Or do any number of otherthings which increase the value of being an MSN member. And,obviously, these tools still interoperate with the rest of theblogosphere (note that Spaces has had RSS feeds since launch).