This is meant as social media for Second Life- so we should have those functions, though be able to opt in or out. One way would be that by default, people you follow could send direct messages. You could opt out of that, in case you get bothered by too many people. On the other hand, by default if you DON'T follow someone they should not be able to directly message you, but a user should be able to opt in to that if they truly want messages from just anyone- they still should then be able to block someone. of course The defaults would be as strict or stricter than those on most social media under that system, so it isn't likely to lead to lots of spam unless you opt in to letting anyone send you messages.