Yes, TGP submissions are worthwhile if a conversion ratio of 500+ is worth the time and effort spent to you. It's free advertising, other than the cost of any additional paid content.

Is the adult industry spoiling blogs? Perhaps any marketer, adult or regular, spoils a tool like a blog if the blog adds no real value for the user. I ran across a PR 5 blog this week that stopped new entries last summer. The blog author found hundreds of marketing/spam (adult and regular) comments to her last entry, so she just turned off the add function.

I do a once in a while blog at livejournal.com mostly announcing what's going on with my websites and any big personal changes. I don't think it gets much traffic.