Just like was said on that site, a lot of signs point to it, enough fans have spread their own feelings that it is true online, at this point for me, I would feel a little disappointed if it was not something completely different. I don't think cannibalism is as shocking a concept in a zombie world as it would have been 5 or 10 years ago.
In fact I'm going to guess that by the end of the first or second episode of the new season, Terminus will be over run with walkers, most if not all the people of Terminus dieing. Ricks group on the run again (after losing a major character *GlenOrMaggie*) with Gareth actually joining them....and we'll find that Beth is alive and well with Gabriel who they'll meet up with in a couple episodes in.