From the comments here it sounds like "Real Man" is a relative term and putting it in a profile without explaination really gives no hint to what the person is looking for. Like someone else said, the poster using this term is lazy and defaulting to an ambiguous term they feel everyone understands as they see it. Using the term in an attempt to foster communication is probably a bad idea because your goal is to get to the communication stage first, then be as vague and ambiguous as you want once you're talking when you can explain readily.

When I read it in profiles it brings to mind a masculine guy, strong willed, who knows what he wants and takes it, a take charge type, just short of being labeled as abusive in the relationship. I close those profiles quickly.