The Mojang servers' uptimes are getting better, but there are (and will always be) some times when their servers are down. Unfortunately some players aren't as familiar with the http://help.mojang.com status checker page so they think it's your server's fault. This can result in players thinking the problem is your server's, which is never good.
Now with MojangStatus, your server motd (the message you see in the server list) will change if a mojang service is down. So your players will be informed before they even enter your server.
This plugin uses Plugin Metrics. This means it will send anonymous data to mcstats.org to help improve MojangStatus. If you really want to (please don't) you can disable this feature in the Plugin Metrics configuration. (Located plugins/Plugin Metrics)
Would you like MojangStatus to automatically check for newer versions available from BukkitDev?
What would you like the motd to say when a Mojang server is offline?