I'm looking to create a (most likely php) web server where a user can log in and send messages over the internet to a C# application that is running in the user's taskbar on their home pc and display a message.
LogMeIn and Dropbox both seem to "push" data to the user's pc without any needed information (no static ip address for the desktop side) so it must be possible but I'm not sure how.
Any help would be greatly appreciated, thanks!