I personally suspect that the referral badges (i.e. Promoter, Campaigner, and Activist) are only awarded when a proposal leaves the "Commitment" phase and enters the "Beta" phase, but I can't find any explicit confirmation for this.
The reason behind that impression is that I was lucky enough to refer, at the time of writing, 60+ committers to the Vim proposal (don't worry, this is not a referral link), a number by which, according to the badges' definitions, I should be awarded the Promoter and Campaigner badges. The proposal itself is currently in the "Commitment" phase, and I wasn't awarded any referral badge yet.
Update: I have just logged in to Area 51 to discover that I have been awarded the badges as expected. Since the proposal is still in the "Commitment" phase, this clearly invalidates the above impression. But the question could still do with an answer: I was originally under the impression that badges in general were awarded [almost] immediately, but AFAICT, I was awarded the Promoter badge around 38 hours after my 5th referred committer and the Campaigner badge around 33 hours after my 25th one (I've too much time on my hands, don't I?).
Furthermore, Atwood's comment on this answer seems to suggest that awarding referral badges may depend on whether those who "commit" actually follow through on their commitments.
So, when exactly are referral badges awarded, and do they require referred committers to follow through on their commitments?
