4) StumbleUpon – Traffic Generating Community
Part of utilizing social media is to help your company and website to get found. If you are a consumer brand this is easier to do, but niche B2B businesses can be challenged just to drive any traffic to their website. StumbleUpon is actually a lesser known 
social bookmarking site, but because of its algorithm and 10+ million users who like to “stumble” or navigate through several sites at time, some studies have shown that StumbleUpon actually attracts more traffic to your website than any other social media site outside of Facebook. My personal experience with StumbleUpon has been the same, even surpassing Facebook. It is important to note, however, that StumbleUpon should not be used just for SEO and it is a social networking platform in its own. In addition, because you will need to be sharing content as part of your social media strategy, think of StumbleUpon as your company’s content recommendation engine. You may not find your Fortune 500 customers on StumbleUpon yet, but I do see an increase in small businesses joining the platform…and there are other compelling reasons listed above that should convince you of SU’s value. (Source: Neal Schaffer, Windmills Marketing)
