I receive between 5 & 20 sms every day at work (and send quite a few too). Distracting? nah. At least I can go check my messages when it suits me, unlike phone calls.
The worst thing is when you're having a conversation/meeting with someone face to face and their phone rings. They stop talking/interrupt you mid sentence to answer it and everyone sits there awkwardly while they chat away at the top of their lungs.
I also feel sorry for retail staff when the customer comes to the counter on the phone and proceeds to point and silently mouth what they want. This is the height of rudeness!
However, I think websites like Facebook are more insidious than mobile phones. Facebook pretends to be about connecting with people, but in reality it's just a popularity contest, time waster (there are 17108 different "Applications" to plug into your facebook

), and stalker's paradise.