Yes, there are different categories depending on what you want to share (game snippets, models, art, etc.). If for some reason you aren't sure where to post it you can just do it in General. Just make sure to tag it properly with the Showcase tag.
I can't see the "New Topic" button in other sections, only here in General. In other sections it says "Note: only members are allowed to create new topics, but anyone can reply."
