One way you're a 'real' member is that I recognize your username and remember you as a distinct user who tends to write about specific stuff. Random new users are just indistinct name mass until they show up often enough to start getting recognized.

Though it probably makes you become a real member faster when your username helpfully describes the stuff you know and will be talking about.

Based on a quick look around this thread, 1000 karma does seem like a reasonably good rule of thumb threshold between an username being obscure and at least vaguely familiar. On the other hand, DataPacRat apparently only went over 1000 just recently but has been making discussion posts for years, so I've recognized their username for a long time now.