Here are my initial thoughts:

As is typical in most franchise agreements, there’s most likely a clause regarding use of the brand name and trademark. It may need some interpretation to Web 2.0 usage, but there should be no problem applying the language in this regard. Also, online branding falls into marketing, and ultimately, advertising. I’m certain franchise agreements provide typical clauses that prohibit franchisees from utilizing non-authorized ads, etc.

All that being said, it’s always best to convince rather than demand. If the organization is large, it may be more effective to work through advertising cooperatives and franchisee advisory councils in pushing anything regarding social media. One strategy could see the franchisor contributing financially to a social media strategy. (Much cheaper than legal expense to enforce clauses in franchise agreement; not to mention “expense” of diminished morale) As incentive to initiate the same, franchisees would need to voluntarily relinquish their online identities so the parent company may establish one facebook page, one twitter id and one website.

I would recommend developing a template for franchisees to use that would piggyback off the national identity. For example, if corporate identity is Zippy Lube, the franchisee could use Zippy Lube NY or Zippy Lube NY 101 or Zippy Lube Jamaica NY and so on. Each franchisee could have their own web page linked to company website. It’s important to maintain uniformity and a sense of organization when attached to company brand or when linked together.