Are you interested in documenting crypto platforms or you really want to make use of them? I know having multiple sources of information is good for research purposes but as a newbie, the more platforms you seek knowledge from, the more confuse you would become.

By the way, you can get more than five platforms that discuss crypto daily but the most prominent ones is this forum and the altcoinstalks. These two are specifically centred on crypto discussions with high traffic on daily basis unlike others that have crypto as subordinate.