if there are more then one person in the conversation, the last person to type it have to strike up the conversation.
bill says: so hows ure work been?? all 120?
Often and repeatedly--sometimes incessantly--used by speakers incapable of beginning an idea at its beginning, those seeking to stall for time until a thought congeals, or those desiring a familiar starting point as they venture into the dangerous world of communication.
Beginning each sentence with "so" has been called "using a verbal tee" to enhance one's chances of hitting an idea squarely.
It suggests that the speaker thinks that more should be said, but there may be nothing to logically follow it.