Website Traffic Team is a paid service that helps you get targeted website traffic. Their site is very clear in explaining where the traffic comes from, too. What they do is work with a company that owns a lot of high-traffic expired domains. Then they work with you to find expired domains that match the niche you are targeting. So if you want people who are interested in cats to find your site, WTT will find some cat-related expired domains and redirect the users who click on those domains over to your site.
I've read about website traffic services which simply inflate your traffic numbers using bots, etc, but WTT gets actual people who are interested in relevant subjects to look at your site. Pretty clever, I'd say.
There's lots of info about how to increase website traffic on the WTT site if you want to check it out. You can even use it for affiliate marketing sites. I have to admit that I learned more than a few things by reading through their FAQ.