Myspace. Google. Twitter. Facebook.

In the past two years, each has been the subject of an enforcement action by the Federal Trade Commission.

But that's not all. In two of those cases, the FTC included claims that the U.S.-EU Safe Harbor Agreement was violated, in addition to allegations of broken privacy promises and deceptive tactics with customers.

Never heard of the Safe Harbor Framework? It's been around since 1998. Enforced by the FTC, the framework is administered by the Commerce Department. Companies that want to do business with the European Union may more easily comply with EU data protection law by voluntarily pledging to honor certain Safe Harbor privacy principles. The FTC has enforcement authority over the program.

After a fallow period in which the FTC brought no Safe Harbor enforcement actions, the agency has started to hit the gas pedal. A bit, at least.

The FTC has brought a small number of cases alleging violations of the Safe Harbor in recent years. Fair enough. But what does that have to do with FTC enforcement and social media companies?

Of late, allegations of Safe Harbor breaches have been nestled into standard FTC privacy and data security claims against several U.S. companies. That's what happened in the FTC actions against Twitter and Facebook.

In the FTC's four actions to date against social media companies, the agency said that Myspace misled millions of users about its privacy policies, Google used deceptive tactics and violated its own privacy promises to consumers in rolling out its now-abandoned Buzz social network, Facebook didn't give users clear notice or get their consent before sharing customers' information beyond their existing privacy settings, and Twitter misled millions of users about its privacy policies.

In addition, the FTC said, Twitter and Facebook also didn't comply with the Safe Harbor Framework.

The FTC's actions against Google, Twitter, Myspace and Facebook all ended in consent agreements. It's worth taking note that the U.S.-EU Safe Harbor is a recent element in the mix, one for companies to bear in mind.