I imagine there are plenty of brilliant and interesting people on the internet that are not aware of HN, but could contribute nicely if they became members here.
This "age elitism" issue is wearying. It happens in other places too (SomethingAwful, for example, went through a hilariously horrible period where the year you registered was the most important part of your post).
But this is supposedly an intellectual forum, not a comedy forum. Grow up and stop thinking the number of days since joining makes you better than someone else.
(Yes, I joined after you. I am also diluting this forum. Get off my lawn.)