Point/joke taken, but let me play devil's advocate: anyone very familiar with regular expressions probably has a lot of experience as a developer. Is s/he a good developer? That's harder to say. But s/he definitely does have some passion for solving puzzles, at least.

I'd even argue that LinkedIn doesn't really even need amazing developers. As far as code goes, they're only really solving problems that have been solved for decades. Infrastructure is another matter, but I doubt they're doing anything insane on that front either.