First, despite the lack of utility of this site's forum and myspace-esque profile features, in major markets there are plenty of models using the casting and availability notices which is decent, and the attributes and tagged photos helps alot. The availability notices are great!

Secondly, Instagram is okay, when it works. The main issue with Instagram is that its not purpose built for this, and it is practically impossible to contact most models this way. The inbox is basically broken with 5 different levels of spam filtering and not appearing in their default inbox, all while their default inbox is inundated with other messages vying for their attention and their active group chats with friends. The other issue being that its not clear what they are willing to shoot, right now, and you don't know their stats either which can be awkward to ask if its not clear what they are familiar with. For me, this has resurrected the utility of going to local workshops solely to see which models are actively booking and showed up.

Craigslist can periodically be useful in a time or place. But the expectations are all across the board. Many people willing to model aren't familiar with a release form and do things for private collections or its all a euphemism to begin with.

I'm not on Facebook but it seems like every town has local groups, but they are all low signal, unprofessional, full of scammers, and people not serious about meeting. You also have to be in those local groups for some time for your own validity to stand out, as its starting from zero in each group, but even then it doesn't work that well.

There have always been other modelling/photographer social networks like MM, but in the past they were kind of irrelevant, has that changed? US market.