Isn't facebook strictly inferior to email for messaging? By a wide margin? It's not archivable, sortable, filterable, searchable, forwardable, or manageable. It can't be sent to multiple recipients. It has no BCC, threading, prioritizing.
From a technical perspective. However, many of my friends respond to fb messages and not emails. Near as I can tell, they're young enough that, when establishing a "best way to contact me," they chose "website I'm going to be on anyway."
I think, now that they're graduating college, they're going to have to get themselves a professional email, but the best way to contact them socially is going to remain fb because, for most social stuff (or at least, social stuff my friends and I get up to), we don't really need any more features than fb has, which I find disappointing, being in the minority who could really use everything you listed.
This thread is for asking the rationalist community for practical advice. It's inspired by the stupid questions series, but with an explicit focus on instrumental rationality.
Questions ranging from easy ("this is probably trivial for half the people on this site") to hard ("maybe someone here has a good answer, but probably not") are welcome. However, please stick to problems that you actually face or anticipate facing soon, not hypotheticals.
As with the stupid questions thread, don't be shy, everyone has holes in their knowledge, though the fewer and the smaller we can make them, the better, and please be respectful of other people's admitting ignorance and don't mock them for it, as they're doing a noble thing.
(See also the Boring Advice Repository)