First impressions are always invaluable and can't be recreated. So here is my 5 pence worth as a random web visitor landing for the first time.
Initially confusing, I didn't quite get the purpose, or why I was here. With no content in my area, you have the age-old problem of lack of content, which then makes it harder to understand the purpose, or motivate any action. Unless you have deep pockets, the fix here is scraping or partnerships, but you need data. Something like NextDoor might be a natural collaborator.
Thought I would add a pin. Echo others about the Yellow, take it from someone who has been using yellow for a long time, in the modern world, I'd think again, particularly buttons on a map backdrop. I think a blue would be warmer and clearer.
So I added a description for a pin, then automatically selected upload, as my eye was drawn to that as the next option. Once I realised it was for images, I cancelled that, then finally saw the continue in the yellow header. In my brain the continue option should have been at the bottom (or repeated at the bottom). Don't let people think, just make it idiot and old fart proof.
So I submitted a pin and it appears you published it straight away. So what moderation is going on? Are you relying on automated filtering and profanity filters etc? If so make sure you have a decent public media insurance policy!
I just did a test one, see below, but I hope you can't just add any old nastiness, hate, profanity or god forbid, let the kids start pratting around!
Nice idea, maybe rethink the colours and flow, but get lots of genuine impartial user feedback, don't steer them, then react to their honesty. I hate internet users, they always prove me wrong, use the site in a completely different way than I intended, and have a habit of finding lots of undocumented features
Best of luck.