This is a platform — or something — created with the goal of being a good place to go on the internet. At the moment you can do a few things: create an account, create posts, or browse what other people have posted. The goal is to build a lot of other things, but to do so mindfully. To see what's in store, check out the roadmap.
At the moment, there is one type of post: a mark, used for sharing links. You don't really need any particular reason to mark something: maybe it was really good and you want to share it, maybe you're keeping track of some research, maybe you saw a funny tweet (really Twitter is better for this kind of thing but you do you).
Filtering and searching can be tricky: when I click on something, do I just want that value as my search or do I want it added to my existing query? Thus wayfinding: a UI experiment for trying to de-complexify search. Green up arrows are for adding a parameter to your search. Red down arrows are for removing a parameter from your search. The up/down arrow is for switching from newest to oldest and vice versa.
No, no it doesn't. Maybe one day. Do you want to give This money? Let us know on the feedback page.