I would like to refer the community to Zawinkski's Law of Software Envelopment[1]

"Every program attempts to expand until it can read mail. Those programs which cannot so expand are replaced by ones which can."

And propose a new, modified law for the current generation:

"Every Web 2.0 website attempts to expand until it can chat. Those Web 2.0 websites which cannot so expand are replaced by ones which can."

1: http://en.wikipedia.org/wiki/Jamie_Zawinski