Hello, I run both and I must say to start a tube you best find sponsors who run 2-3 min clips minimum to have a chance of any returning visitors (= growing traffic). also if you are making a niche specific tube, like shemale or anal sex that will work better in the long run then just another tube site that thats a little of the same thats available anywhere.
I am now testing with RSS feeds for the tube updates and that really boosted traffic and sales to the tube, people can then use your daily video updates on their blogs etc. and that will drive people your way. and help you boost links to your site
