2leep.com is good for gaining more traffic by fair, 200% stream exchange. Meaning you send them once, 2leep give you twice the traffic.
Best part of 2leep?
1) Free to join, but they are selective (need to be old blogger, with some reputation and nice interesting contents).
3) Many ways of getting links (insert their widget into your blog, popup under, directly exchanging links with other posts from other bloggers etc).
4) Also, you are eligible for affiliate programs (no money involved), in which they pays you 5% from the total of your downlines traffic.
Bad part of 2leep?
1) 2leep is addicting. Makesure your contents are interesting enough or else, your visitors would be easily leave your blog for other interesting contents inside the 2leep.com network.
2) Adsense? There is no clear statements about whether 2leep.com widget can or can't be used with adsense publisher network.
2leep.com review video:
Example of live 2leep network widget:
Click! Join 2leep Now!