FMAN has only been spotted walking around in Crystal Sands (in the Aldan world only). He has never been reported to actually chat with other Jammers. According to some of the first FMAN witnesses, his den (basic nonmember design) is completely empty. Now, the den is locked. Sending him a Jam-A-Gram has been shown to increase your chances of getting a "hack-gram" from him. Make sure not to accept the Jam-A-Gram gift if it's from FMAN122.
FMAN's username has been approved by AJHQ, so if you are sent a Jam-A-Gram by him, it will say it is from fman122. Before, he would send a Jam-A-Gram that would say it was sent by a New Jammer. However, when you clicked on his name, it would show a wolf nonmember - and nonmembers can't send gifts! That should have been an automatic sign that something's odd, but still, many Jammers accepted the gift and their accounts were "stolen" (although this has never been proven) by FMAN. Hopefully, AJHQ will get rid of this monster if the rumours are true!
Me with the FMAN account