Not looking for an IM program as much as something I can leave small text files for users with, regardless of what computer I send it from. Almost like electronic Post-it notes that'd require a password to read.
Have looked at a few so far but most have way too many features, or only function for instant messaging. We're a small business with under 12 employees. I just want to be able to open the program, select a name, type a short message, and have them receive it the next time they're at their computer.
My co-workers are asking why I don't just use email

Any suggestions?
Thanks