You know those "introduction" emails? Someone thinks you should meet someone else, and emails happen about it. Or it's you doing the introducing, either by request or because you think it's a good idea. Cutting to the chase here, those emails could be done better. Eight years ago, Fred Wilson coined the term "double opt-in intro".
This is how it can work.
You're doing the vetting
Since you're writing the emails here, it's your reputation at stake here. If you do an introduction that is obnoxious for either side, they'll remember. Make sure you're introducing people that you really do think should know each other. Like a bizdev cupid.
You're gonna do two (or three) times writing
The bad way to do an intro is to email both people at once. Even if this introduction has passed your vetting, you have no idea how it's going to turn out. There is a decent chance either of them or both aren't particularly interested in this, which makes you look like a dolt. It doesn't respect either of their time, puts your reputation at risk, and immediately puts everyone into an awkward position (if they ignore it they look like an asshole).
Instead, you're going to write two emails, one to each person you're trying to introduce. And you're not going to reveal who the other person is, except with non-identifying relevant details and your endorsement.
They do the opt-ing in
If either of the folks are interested in this introduction, they can email you back. Give them an easy out though, I'd say something like "if for any reason you aren't into it, just tell me so or ignore this, I promise I understand". If you don't make it easy to blow you off, it's your just transferring the awkward situation to yourself.
If either of them isn't into it, it doesn't matter. They don't know who the other is and there is no awkwardness or burnt bridge.
If both are into it, great, now it's time for the third email actually introducing them. Get out of the way quickly.
It's about more than awkwardness and reputation, it's about saftey
It's also why double opt-in intros are *a must*. Please please please don't go intro'ing people to each other without asking first.
— Lara Hogan (@lara_hogan) August 5, 2017
Just because you have someone's email address in your book doesn't mean you should be giving it out to anyone that asks. Better to just assume any contact info you have for someone else is extremely private and only to be shared with their permission.