what is drupal

I propose we come up with a (or several) reusable DESCRIPTION(s) of Drupal for use in proposals to clients... you know, the people who aren't geeked out on Drupal, and, quite the contrary, have no (expletive) clue what it is, or what it does.... and mainly, WHAT THE BENEFIT(S) IS OF DEVELOPING IN IT IS(ARE).

I feel like descriptive text should distill itself down to about 2 sentences that provide a widely applicable (and perhaps wildly general) concept of why clients should commit to the Drupal platform.

Here's my stab: