As this graphic suggests most small businesses that are using social media use Facebook and LinkedIn. Twitter usage is relatively small, even smaller than blogging.
Interestingly 50% of small businesses complained that using social media takes more time than they expected. 17% believe social media gives customers an forum for complaining, and 6% believe social media has hurt their business's image.
The main takeaway from this data: Social Media is a great resource for small businesses, but it isn't magical. Any marketing campaign takes effort and planning, and that includes social media.