You want a great example of this, look to the man who more or less invented the principle- as I've used news.YC over the past couple of weeks it seems every few days, as simple as the site is, very nice features keep popping up. Nothing disruptive, nothing gaudy, just smooth and steady increase in value. In fact, if you want a great example of a site that's responsive, that knows how to grow a community, that knows how to fill itself with quality community content, that does something people want and does it simply and well... Thanks for leading what you preach.
It's cool how even though there is a lot of noise surrounding advice about startups a bunch of precepts have an air of unanimity. "Release early and iterate" would be one of those.
Here's a blog post by Aaron Swartz: http://www.aaronsw.com/weblog/rlrr
In there, he proposes that "release early, release often" works in open source, but is less applicable to a wide public who are not expecting something unpolished and incomplete. When you only get one chance to make an impression, the unveiling might need a lot more consideration. Of course, then your product might never even see the light of day because it's been tied up for so long.
This is a different view from that in PG's essay, and it just shows the added complexity in decision-making a startup must go through.