It's good to be explicit about what content you are seeking, as historically spots like 500px were very photo-centric, and other places were a catch-all for anything and how sites gain an identity/curate/attract users can be strongly affected by those early choices (disclosure: I've used dozens of these kinds of services over the years, and even worked at one -DeviantArt- at one point, so my view is only partly anecdotal :)