Google have launched their new blog search tool, which like their news search tool obviously needs to keep track of a vast number of web resources.
It is still early days for the tool because its indexing appears to be several hours behind (either that or they forgot to set their timezone). For example a search for Java shows the latest entry as from 5 hours ago. Whereas specialist aggregators will be typically under 1 hour behind.
Where it does win is the way that it is a search tool and thus a complex filter. Javablogs is an opt in environment where anyone who mostly talks about Java opts into the aggregator. This means that sometimes you get stuff that is unrelated, and sometimes you miss good content on 'not normally Java' blogs. With the search you get what the Google engine considers relevant, which means that you may miss all those blogs on Ruby (shame :'( ).
The 'link:' and other search options are supported, which is an improvement on the javablogs search (which rarely works anyway).
The really good feature is the atom/rss feed option for a search. That really is a nail in the specialist aggregator coffin.