Mr. Number is an application whose main function is blocking unwanted calls and text messages, whether they're from a single person, a specific company, a particular country code, or even a region of the world. If you don't want those calls and messages, you have no reason to receive them.
From the application's simple interface you can select the numbers you want to block or mark as spam. You can even intercept an incoming call and automatically transfer it to your voicemail. Also, thanks to the 'Caller lookup' tool, you can find out exactly who's calling even if they've never called you before.
One interesting feature lets you report telephone numbers or text messages as spam. What's the point of this? To notify other users. If many users report the same number as spam, a potential spam warning show up for other users the next time they receive a message or call from this number.
Mr. Number is one of those applications that seems to be more useful the more you use it. After all, why put up with calls you don't want to receive and text messages you don't want to read?