My guess would be that they were all from EOM. I know the posts at GIM were signed Amer El-Maati but EOM has claimed to be that guy before so there's nothing new in that.
I think EOM's system is that he trawls about listening to people's guesses about dates and then posts in line with these periods of time. For instance, he suddenly seems to be posting a lot at the time when Bin Laden's truce period is ending. I think he's betting on the chances of an attack. Whether he knows anything is doubtful.
I'm thinking that as well, but I'm not entirely sure. It has almost the exact same tone and spelling as previous EOM posts, but is credited to Amer El-Maati. I somewhat recall him posting as other people, and I'm sure Amer might have been one. I thought it sounded familiar.
These new posts also sound just like his first posts, that I had previously forgotten. It seems everything is exactly the same, but a little more threatening and possibly with a little more truth. I'm mostly curious to know if the posts were actually sent to GIM, or if she found them at the CNV board EOM hangs out on.