Registration has opened for the Word of Mouth Market Summit 2008, in Rio, this November. I'll be anxious to see the conference agenda when finalized, to see if there's much research presented on paid-blogging.

It seems every day I run across a new tool or service that allows bloggers to monetize their efforts, and although there have been studies and market size estimates on the WoM market, I haven't yet seen many specifics on paid blogging. Izea launched a new paid-blogging ad network, Social Spark, at AdTech earlier this year, and I can think of roughly a half-dozen other similar networks.

Of course, the market is confusing - bloggers can monetize their blogs with display ads, Google/Yahoo/Microsoft ads, in-line text ads, blog sponsorship, paid posts, just to name a few. But is there really anything different about banner ads on a blog from banner ads on a non-blog website? Should such ads be segmented as part of the "blog market"? Or lumped in with the overall internet display ad market? As the market matures, I think we'll have to see breakdowns of spending on these different blog vehicles.