I read this interesting post via Etsy's advice for sellers page. It gives insight into small businesses and their
most popular online marketing tools, here are some of the statistics; Twitter: 45%, Facebook: 33%, Linkedin: 14%, Other: 7%, Youtube: 2%, 4sq/Bebo/MySpace: 0%.
Please bear in mind, when assessing which marketing tools would be best for your own online marketing strategy, these figures merely outline the most popular. The statistics above do not necessarily translate into being the most effective marketing tool, for your own business. In my experience good old fashioned trial and error is usually the best way to evaluate the best options available to you.
Try focusing on 2 types of network, i.e. your blog/website and a social network site which facilitates links back to your main site. Remember to add google analytics or some type of statistical tool to analyse and monitor the 'who and where' of your customer base.
Statistical Source: Etsy