In case you haven't seen, a group called Coalition of Americans for Political Equality (CAPE PAC) was running some online ads for Senator Scott Brown, which runs afoul of the agreement between Brown and Elizabeth Warren to discourage third-party advertising in the race. (I believe WCVB broke the story.) The Brown campaign communicated to the PAC their desire to have no third-party ads, and CAPE PAC agreed to stop. Brown will pay half of what the PAC spent -- a few hundred dollars -- to charity, under the terms of the pact.
A couple of people asked me whether Brown's campaign may have violated FEC rules against coordination with third-party PACs. So I checked with the campaign, and they tell me they sent an email (the contents of which are posted on Brown's web site) explaining the agreement, and expressing Brown's "strong desire that outside groups, including those who wish to support him, abide by the terms of the Pledge."
The wording was clearly intended to be as generic as possible, and a campaign spokesperson says that it was vetted by the campaign's lawyers to make sure it didn't go over the line.
It all seems kosher to me.