It's always funny when people attention whore like this.
It should honestly be treated the same as leaving posts.
"I'm back" topics atleast. Just, not "Hello/Hi I'm new" topics.
The odd thing with these "I'm back" topics though is that the OP tends not to be someone you've probably acknowledged before. Usually it's someone who you still won't notice afterwards anyways.
Also, if you were recognized by atleast a few people previous to your "Leave", then surely just posting normally back into the Forums would have you noticed by those people. It would seem more normal if someone were to start their account, use it, take a break for whatever, come back and continue posting normally.