The Winklevoss twins are going after Facebook from an alternate argument.

Previously, Tyler and Cameron Winklevoss pursued the valuation argument, alleging that Facebook failed to disclose the proper value of their shares during the 2008 settlement process. 

As a result, they allegedly received less than the $65 million stock and cash settlement they were supposed to receive.  This angle, however, has been rejected by California courts and the twins are abandoning it.

Now, they're resuming a case in Boston under the argument that during the 2008 settlement process, Facebook should have disclosed the conversations Zuckerberg had with his associates in 2003 and 2004 regarding Facebook.

These messages show that Zuckerberg, who was hired to work on the Winklevoss twins' social networking site, intended to delay his work for them so that his own social networking site (Facebook) could launch first.

These conversations were leaked to the public in 2010.  Below are some highlights of what Zuckerberg said:

they made a mistake haha. They asked me to make it for them. So I'm like delaying it so it won't be ready until after the facebook thing comes out.

So you know how I'm making that dating site [the twins' website].  I wonder how similar that is to the Facebook thing.  Because they're probably going to be released around the same time.  Unless I f*** the dating site people over and quit on them right before I told them I'd have it done.

I'm going to f*** them. Probably in the ear.

The Winklevoss twins' settlement in 2008 was $45 million in private Facebook shares and $20 million in cash.  Because of the recent appreciation of Facebook shares, their settlement is now worth hundreds of millions of dollars.

A judge who ruled against the twins in the California case said this: They made a deal that appears quite favorable in light of recent market activity. At some point, litigation must come to an end. That point has now been reached.