Photo Communities (flickr, 500px, smugmug,.. just to name a few from 1000's in the web) are always a good way to find inspiration, ideas and exchange with other photographers experiences. I saw dozens of this portals coming and going over the years and the broad market is dominated by a few big ones, the rest are all kind of special and small communities (certain camera brand or topics).
What almost all communities have in common is the noise-factor, it is incredible high. I am not talking about bad images, anyone learning and picking up photographic skills should post his work to get feedback. I am talking about the comments !
Of course, everyone is happy about positive feedback or gets his work praised, but either photographers get dozens of one-liner comments ('perfect, well done, super, great') or NO feedback at all. Just drop by popular images in Flickr and you know what I mean. How can anyone learn or advance in his knowledge and style ? We (human) don't like to be criticized and also are shy or hesitant to tell someone that we dont like his image of (better) how to improve it or maybe just some feedback which is more than "Awesome".
That what I like on 500px.com, you can click the LIKE button and if you don't have anything useful to say, don't do it !
Something that disturbs me at large on Flickr are the groups for 'masterpieces', the comment section of some images are filled up with invitations to join or submit the image to this and that master group (on invitation only).