Pinterest may not be anything like Facebook, but it's still a social site at its core. It's just that most of the interactions are indirect.
Now though, it's possible to send pins directly to friends, so you can make sure they see something you pin or something that you stumbled upon and like.
"Just tap Send from either web or mobile to send a pin. You can send pins to fellow pinners (if you both follow each other), Facebook friends, or email contacts. We'll show you the most recent people you've sent pins to for easy access," Pinterest explains.
You can send pins from the web or the mobile apps and your friends will be notified of it, either via the built-in Pinterest notifications or via email.
The feature is not completely new. Users could share pins via email, but everything is now much easier. The feature is rolling out in the coming weeks, so you may not have it yet.