{{{ "The character of the crowds is made up of mimicry and hostility."
- -- Franz Grillparzer }}}
The canonical business plan: aggregate a large N, charge large % of N $, repeat - go public or sell to Microsoft. Of course your not doing it right if there isn't something to make those little n a little sticky to you...
These sites (in no particular order!) host Blogs for people.
Blogger -- http://www.blogger.com/
FreeRoller -- http://www.freeroller.net/ (non-commercial)
Of course if you have multiple authors then a blog begins to look like a mailing list. Then you'd have to enumerate all folks aggregating large numbers of mailing lists.