People typically say "I hope you are well" or "I hope you are doing better than before" to show concern, that they do wish you were not so down and do wish you were feeling better. Online you can't say "Hey how are you" in these threads as easily as chat, so when saying "I hope you are well" I believe most people are posting because they know it wont be responded to as quickly as in chat and genuinely do wish you the best