Well, extra time (possibly the biggest barrier), money (but really not much) and people. With social media being so time intensive, and best results coming from directly being involved, the barriers to entry get higher as a business gets smaller, but not insurmountable for those willing to put in the time, especially since it can be done at all hours, and some of the most effective times to connect via social media are very early in the morning and very late at night.
Twitter has not been readily accepted as a small business tool yet but there are those who are having a great deal of success using it in many ways. So why should small business be using social media at all? The most prominent reasons are responding to customer questions, networking and education… but there’s more. To date, most small businesses have not been looking to help build the sales funnel through these channels. This is interesting considering some of the success that can be found with a small business that gets it. And for those who do, and execute effectively, the opportunity to directly facilitate and create sales are out there and have the potential to be huge since the volume of additional sales that can make a difference are fractional compared to what it takes for a large organization.