This is the MOTD that people will see when they first join the server, before they choose what team they go on. You can edit this however you want, to make a nice fancy MOTD if you desire. You can add things like your server's name, your server's rules, a list of admin, or whatever. It uses HTML, so if you know HTML you can also configure the text styles and colours.
Fixing the MOTD scrolling problem
I noticed on my server, after I had added a bunch of lines to the MOTD, that the MOTD needed to scroll. It was too much text to fit on the screen at once, so the MOTD had a scroll bar. For some reason, though, dragging the scoll bar did not work. The scroll bar went down, but the text did not move up. It made it impossible to read the rest of the MOTD.
To fix this problem, delete the following line at the top of the MOTD:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/1999/REC-html401-19991224/loose.dtd">
I have no idea what that line does or why it breaks the scrolling, but removing that line fixes the problem.