Looks like a hot business to go into nowadays, with Calacanis as a role model and successful case study of selling WeblogsInc. to AOL. Similarly I also know about some local initiative about to hit the Romanian market - though insignificant in absolute numbers the local internet industry seems to wake up, with money coming especially from media companies. And even though they still don't get it, I guess it's an important phase for creating the proper grounds when going to the next level.

For what it's worth, here is a list with some of the most important international blog networks.