That still wouldn't change the fact that it'd have to insert the PM for every user which could bring a heavy load to the server not to mention could take up a lot of space depending on the size of the message (if the message itself where say 50kb, and you have 4k users, that's 4000 X 50kb for the PT itself (yeh, that's 195.31 mb) you'll end up with quite a bit of wasted space that will have to loop through every user to be inserted so it could take quite a bit of time to do in the first place); IMO the system message option is a perfect answer
