I've done a handful of interviews over the years, and will be doing more this year (both as an applicant and as a faculty member). I've gotten a handful of thank you notes. I give people my information in case they want to contact me with any questions, but I certainly don't expect thank you notes. And the ones I have received usually come in long after I've rated the applicant (as in, I rate them on the same day I do the interview, and might or might not actually remember who they are when the note comes across my desk). I did get one from an applicant who ended up matching with us, and it was nice to see that she sent me something when I was going through my email later, but even on match day, I didn't remember that she sent anything.
