I don’t think I’ve ever been foolish enough to put my cell phone number online, or anywhere else the general public could see it. This is why.
The operator of the Textastrophe site has a “hobby” of entering into text message conversations with people who have put their mobile phone number out for the world to see. From the site:
Next time you post your phone number in a public place, think again. This is a collection of text messages I’ve exchanged with people who have done just that.