Querying Ettiquete

The broad answer is "it depends".

Some agents want to know if you're submitting to many agents at once. (I had one ask, when she requested my partial) Most just assume that you are and don't even think about it.

You do not really need to worry about notifying agents of each other's existence unless one of them actually offers you representation. Then it's considered good form to let any others with partials/fulls know that you've either gone elsewhere, or that they have competition.

And two weeks on a partial is WAY too early to nudge. I waited 4 months on one, and I"m going on 5 months on another. Patience, young padawan.

I think it's assumed that multiple agents are reviewing queries and partials at the same time. I wouldn't call attention to it if I were you because it really doesn't matter to the agents reviewing. In fact, it could have the opposite effect in that they set yours aside once you let them know others are looking. It gives them a reason to reject. I had about a dozen partials out at one time and never mentioned the multiple reviews because I didn't want to "rock the boat." Agents don't get serious until they ask for the full, then you might want to inform others who also have fulls. I never did unless they specifically asked.

ETA: Tas and I posted at the same time! Everything she said. And absolutely give it at least 3 months before nudging on a partial or you could get perceived as a pest.

I agree with Tas and Karen.

I'd just say that I also wouldn't let any agent know about other partials or fulls unless they specifically ask.

IMO, if you want to nudge an agent, just flat out ask for a status update (politely, of course). I had the same instinct you're having. I wanted to let agents know about other partials and fulls because they'd get a fire lit under them because they'd be worried about losing me. Yeah, that was a bit naive. Luckily, reading these boards, I realized that that kind of nudge is transparent and annoying.

And you do have to wait a few months.

(One slight modification -- I have used new short story publications as a hook for nudging agents -- hey, look, here's another credit for my letter -- but I only do that after a few months have passed.)

I usually don't tell unless one of the agents specifically said "no simultaneous submission." Otherwise, it doesn't really matter until someone offers me representation.