This is nice, what features do you have in your mind beyond this ? Do you plan to add randomisation where you can meet whoever is available in that region(let's say supermarket) beside your normal friends ?
Randomisation is one I've thought of before, but ultimately rejected because it's a thing I've played with in the past and never liked. I dunno if you remember an app called Urbanspoon from back in the day. It was basically a randomized Yelp. More often than not, I didn't want to do the randomised activity, so I'd just spin it again and again and then get frustrated and go to my normal places. But maybe that's just me.
I do have a couple of other ideas, though.
One idea is to re-holler. If I say I'm going to this brewpub and that hollers out to my friends, then one of my friends could say "Yeah, I'm going here, and I'll invite my friends, too." But then you start getting into some weird network effects that might be problematic.
Another is the idea of personas or profiles. There are events where the acceptability of your friend group changes. If I'm going to a farmer's market, it's totally appropriate to have a coworker join you, but at a BBQ at my house, I'd rather not have my coworkers join. Similarly, my family can join a BBQ but I'd rather not meet them at a professional conference.
Similarly, there are some events where I think it's OK to bring a plus-one and in other circumstances absolutely not.
Another concept is that sometimes I might go to, say, ComicCon with some friends in a faraway city. Now my definition of "local" has changed, so if I holler while I'm in San Diego, my friends back home in Boulder won't be able to attend anything -- but my friends that are with me at the convention might totally want to know what's up. So having some sort of mechanism for saying "I'm not at home base, I'm somewhere else and the rules are different" might become useful.
So far I've rejected all of those for one simple reason: they increase friction. I want this to be as simple as it can possibly be to hang out with my friends. The more friction you add, the less likely people are to keep using it. At least, that's my philosophy. So I've rejected just about every other feature I can think of.
For example, for farmer's market, your profile will be visible to only coworkers at that time and when during bbq at your house, your family members can see it. It's a one time setting, I think it's cool.You don't need to built it instantly, you can go in phases.
I think Insta has rolled location thing, but here I'm talking about location + personas, I hope you understand my point and I'm not making it complicated ?
And as you approach the "coworkers vs family" problem, you start to drift toward individual invitations, which again adds friction and decision making.
What I think I've settled on is the least friction for the most value. It's not perfect, and I'm not chasing an endless roadmap of features for the sake of features. I've hit upon what really works for me and my social group, so I'm trying to be really, really thoughtful about any additional features.
I do have a draft of personas on my beta app, but I'm not totally happy with it, so I'm going to continue tweaking it and testing it with my social group before releasing it.