>I really prefer people to warn me before dropping a bomb
Why? These "hi" or "are you there" or "can I ask a question" are useless to me. Also in the reverse role I find it useful to just type up my whole problem. Sometimes in the middle of typing it all up I will figure out a good solution and then just not send the message. Even if the person is not there to help you, you can always copy paste your message to someone else.