Disable all Spammy links (e.g. bitly)

It seems that the spam is getting out of hand lately. There is a self-promotional link to some garbage scheme in nearly every IH newsletter or something completely irrelevant to the group.

Wouldn't it make sense to blacklist link-shorteners and spammy sites for more transparency?

IMHO links to youtube.com videos should also be banned.

Alternative: Only let older accounts post (maybe >3 months?)

or a combination of both.