One thing webmasters and web developers need to master is social bookmarking. If you manage a website and don’t know what social bookmarking is then you have fallen behind in times. Don’t worry though! The art of social bookmarking is really not that complicated and can send some good quality traffic and backlinks to your website.
One thing to look for when submitting to a social bookmark is whether the links they provide are dofollow or not. The term dofollow means that a search engine will count the link as a valid backlink to your website. A nofollow backlink means the search engine will basically ignore it and never know its there. One important step in seo is link development. The more quality backlinks you have pointing to your website, the more it will help your rankings.
When you submit your website to a dofollow social bookmark you are not only getting the opportunity for free traffic from it, but also a backlink to help your search engine rankings. StumbleUpon is a nofollow social bookmark but I personally like to make an exception for it. It’s the only nofollow social bookmark I submit to simply because it sends excellent traffic. If you can contact friends and family and ask them to “stumble it” that can help you get even more traffic from it. Visit StumbleUpon.com and download the toolbar to start “stumbling” your websites. Here is a list of some other dofollow social bookmarks you should visit and register to submit your sites to. These sites will not only send you some traffic, but also count as valid backlinks!
Backflip
Mixx
Reddit
Spotback
Folkd
Business Planet
Wirefan
Content Pop

I personally use StumbleUpon and also receive excellent traffic from it. Make sure you select the correct categories and don’t make your reviews look spammy. If you do so then I wouldn’t expect to see much good traffic from the site.