According to Red Herring:
... environments with distracting technologies lower IQ by an average of more than 10 points when compared with quiet conditions.I am skeptical about such claims and wonder whether bad reporting on pseudo-scientific research is more damaging to your IQ. However, I applaud Hewlett-Packard's Guide to Info-Mania. I especially like the section on improving meetings by reducing interruptions and casual attendance. Check it out.
By comparison, other research has shown that smoking marijuana causes just a 4-point drop. A 10-point reduction is similar to the impact of missing an entire nights sleep.