It’s easy enough, sure, but there are still (surprisingly!) a lot of bad choices out there. I see people starting real blogs on Tumblr, which to me seems like a bad idea.
As for the messaging apps, sure, whatever works for the information you’re trying to get out there I guess. I think if you just want to reach a big audience and spread some message, your best bet is probably good old Youtube and podcasts, which have a very high consumer:producer ratio, but they’re more work obviously. The tweet I wrote this about specifically mentioned a niche food blog, and was from a professional writer, so I imagine he has something specific in mind that wouldn’t work on Snapchat/Youtube/whatever