UTF-8: General? Bin? Unicode?

I'm trying to figure out what collation I should be using for various types of data. 100% of the content I will be storing is user-submitted. My understanding is that I should be using UTF-8 General CI (Case-Insensitive) instead of UTF-8 Binary. However, I can't find a clear a distinction between UTF-8 General CI and UTF-8 Unicode CI. 1. Should I be storing user-submitted content in UTF-8 General or UTF-8 Unicode CI columns? 2. What type of data would UTF-8 Binary be applicable to?