What about copying the contacts from a rival or former company? That is also disallowed, although the legal precedents are still being worked out in the courts. In some cases courts have found that a company's contact list on their social network site is public, while other courts have found that that is not the case.

Also, not every social network is the same. Facebook grants members only noncommercial rights, but LinkedIn is designed for professionals to use in building up contacts, so usage of its information for commercial use may be all right.

So, on which social networks should you build a page and collect friends and contacts? If you already have a mailing-list program, you can use it to find out which social media services your clients use. The program employs MailChimp-generated mailing lists to crawl social media sites and return raw numbers of contacts using Facebook, Twitter, and LinkedIn, among others.

From such results, you can learn which media your clients prefer so that you can better target your marketing campaigns. You can then design video and even applications that best appeal to your audience.