To further drive that thought home, my company hereby offers to add any 1-day-effort feature request made by any popular tech figure, provided they're willing to share our work with their audience. (Sites for those would be http://bug.gd or http://www.yumbunny.com or any other site in my profile.)
Seriously, they'd be silly not to have taken pg up on this even if he wasn't helping to back them.
I don't think pg implied that he bullied them into implementing this, only that he talked them into it. And I can't imagine that YC would last long if pg got into the habit of bullying its start-ups into implementing his personal requests.
While solutions like DropBox or Sharepoint allow versioning and collaboration it's at a higher level. Maybe I've been spoiled by VMWare, but I love having branches of specific versions to fall back on and test things out. Why should writing be any different?
You often talk about releasing early, building something people want, etc. Since you carry a lot of influence, and (I guess) invest in Etherpad, and they've adjusted it to your personal request - do you worry that this effect might give you a distorted view of how well Etherpad specifically, and YC startups generally, are building what people want?