Stumble upon

If you don’t know what this is where have you been living for the last year? Stumble upon is a social media site that installs a toolbar within you browser, you then select your category of interest and then press the green Stumble button on your toolbar this then take you to a random site on the topic you have selected. User have the ability to vote thing up or down which reflects the amount of times it is randomly brought up in the select categories all the link are no follows so it can’t benefit your page rank so from a SEO point of view it not very useful. Although if you look at it from a internet marketiing point of view it can bring you a lot of direct traffic to your site for not a lot of work I believe it is best used with in hobby related ecommerce sites. One bit of advice on add your index page and not the whole site this is missing the point of it and will eventually get your site banned from Stumble upon

Work.com

Work.com is a free article submission web site for business question and answer, you register informing them your business specialises and then you can begin writing your articles with the appropriate links, work.com does pass page rank and is free to join although to get a decent page rank you have to spend a lot of time promoting your self on work.com and around the web.

Other social media site that pass page rank

www.indianpad.com
www.furl.net
www.killerstartups.com
www.dzone.com
www.care2.com/news/
www.zimbio.com
www.clipmarks.com
I said too much already

In conclusion social media can be very useful SEO tool but require a lot of knowledge and effort and has many pitfalls IE they don’t pass page rank or don’t get to your target audience. You can easy waste your time and my recommend is to let the expert handle it clicks here for that expert.