The generally accepted meaning is that already having something (the bird in hand) is worth more than chasing after things that you don't have (the birds in the

The generally accepted meaning is that already having something (the bird in hand) is worth more than chasing after things that you don't have (the birds in the bush). So in this case, the idea is that customers you've already acquired are worth more than a larger, untapped market. The poster has flipped this accepted meaning to suggest that Perl should chase after new users, rather than focusing on keeping existing users happy.