Where is this traffic coming from and is it worth keeping??

[joenobody211]

ive been looking through my stats (awstats) and have noticed over the past few months there are days when i will get anywhere from 100-1000 visitors from these sites --> for-your.us.tt and wkcash.com Both sites just lead to an adult friend finder sign up page. I am not nor have i ever been affiliated with adult friend finder. The majority of my traffic comes from link lists and search engines. Why is this traffic coming to my site? why is the referral page adult friend finder? is this traffic worth while or should i try and block it from my site??? Thanks!