See this this story about the legal status of Americans Elect in Maine. Soon, the Maine Secretary of State will be notifying all Americans Elect registrants that their party did not retain its spot on the ballot. These voters will be given a chance to re-register, but those who don’t respond will automatically be converted to independent voters. Americans Elect only had 58 registered members as of November 2012.
In Maine, a qualified party goes off the ballot if a general election is held and fewer than 10,000 registered members of the party vote. Because Americans Elect had so few registrants, it was literally impossible for it to retain its spot on the ballot. In effect, Maine requires a party to have approximately 13,000 to 15,000 registrants to remain on the ballot. If a party did have that many registrants, it is extremely likely that 10,000 of them would turn out to vote in a presidential or a gubernatorial election, so a party can remain ballot-qualified in Maine indefinitely even if it never runs any candidates.
Meanwhile, Eliot Cutler, who was on the board of Americans Elect, has hinted that he will again be an independent candidate for Governor of Maine. See this story about the 2014 gubernatorial election.