Are Thank You Notes Necessary?

I have never seen thank you notes following an interview through a recruiter help anyone get the job. In fact, these notes can hurt you if they contain typos, grammatical errors, or insincere/boring platitudes.

One big exception is if the interviewer is a stickler for etiquette and expects that thank you note. In that case, definitely email and snail mail your thanks.

How do you know if your interviewer is expecting a note? For one thing, your friendly recruiter will tell you.