Note: I'm not an appraiser, my specialty is Marketing Analytics, so my opinion comes from that angle.
Dude, I'd hang onto this one for a while. The Blog segment is only in it's infancy and I think in a few years you could have something.
At NSI we ran our business on the assumption that the domain market would run in three phases; early adopters/big businesses, small businesses and savvy consumers, then mass market/vanity. The third phase has been slower to take-off than any of us expected, mainly because I think it's taken a while for a compelling consumer web application (context = "Use," not "computer program") to develop. Blogs could very well be that application.
I believe the Blog segment AND the mass markets /vanity domain segment are in their embrionic stages. Both could take years to develop in tandem, or they could find one another and have triplets. Either way, when both markets are beginning to gain critical mass, your SexBlog.net domain will, I think, be of significant value (extension considerations aside).
...unless of course someone comes up with a better name for these WebLogs. I think Blog is about the STUPIDEST name any fad has ever attached itself to.
ps - To help demonstrate my vision of the prototypical 21st century domain owner, tomorrow night I'm going to set up MY OWN Weblog (blog) at LoudPuppet.com!
