Showcasing your images on the web should first and foremost start with your own dedicated photography website. But it should go well beyond that or else all you’ve got is a message with no carrier pigeon or medium to spread the word. Additionally, modern photography marketing is all about social media, interactions, and generally interchanging ideas and commentary.
There are loads of photo communities out there with some being better than others–but this is relative and very subjective. What’s important are choosing the best ones for you.