It's not true. Memphis is not going to join the Big East. East Carolina, no matter how much they grovel, is not joining the Big East in football. I am sure they have asked very politely and persistently. And I am sure the football schools in the conference started thinking "you know, that's not such a bad idea, is it...?"
But it doesn't work unless the conference is going to break in half, which is an issue that has been raised for years. The football schools and non-football schools have different priorities, and even different histories. 8 are private Catholic schools with low-level or no football, and the rest of the schools are public (except for Syracuse) and strive for BCS football berths (though some are much closer than others to top-25 status).
Memphis and East Carolina will keep trying to jump into the Big East, trying to join with the bigger-revenue boys.