worldsex.com is one of the top 10 TGPs so you may lose traffic to them. It's unlikely to be the other way round as most adult surfers look for .coms. I think you will find it difficult to sell the name, but you could make money by running it as a free site and submitting galleries. I'd split the galleries into sections based on country to give the site a different character. Latina and Asian are good categories for example. I don't know if the .co.uk will give you any problems. I don't use them even though I'm English.