I finally revamped 100porn.com as 90% of the sites I was promoting on it no longer existed. If a site has traffic, I'd play with bringing a site up to current web expectations, swap around who I'm promoting, and see how that does before dropping a site.

I'm more apt to drop a domain name that I never got around to developing, and realize it'll be a longgggggg time before I get around to doing whatever needs doing to get it live. Or I'll drop a name, that after i've had it for awhile, realize it isn't all that good a description for what I had in mind originally.