Prof of concepts can be posted if they are interesting, whatever interesting mean and whatever the hivemind thinks is interesting.
For something like this post, a site that works only in one city may be fine, but a waiting list no.
For personal projects you can take a look at https://news.ycombinator.com/showhn.html but similar criteria apply to other projects like blog posts. It's not necessary that they are 100% finished, but they usually get more traction when they are well written and interactive and it's clear it's not a stupid thing that the author did in 5 minutes. Warning: You may get unrequested feedback!
PS: Looking at your comment history, most of them are too short. It's generally better to write longer comments. It's not a hard rule, but it takes a few years to guess when a short comment is a good one.