I’m intrigued by a tag based rather than subcommunity based system. I have a personal wiki system I use that is tag based, and its great since most notes fit in multiple categories. Different from a social board though.
Re images. A giant image, or an animated gif in the middle of a text discussion can be disruptive. The same with things like fancy user sigs that are 10x the size of the comment they posted. Do you have thoughts on how to limit this kind of distraction?