Advice to entrepreneurs: when to sell

Buried in the comments of a recent A VC post, Marc Coullier (posting as "bpm140") has some great advice for entrepreneurs:

I learned a valuable lesson with the MyBlogLog acquisition that I've passed on to at least a dozen startup founders who ask me about my experiences. I'll post it here to that I never have to say it again:

Figure out exactly how much money you would need never to improve your product again. If they offer you that much, take it and don't bitch when you never get to improve your product again. Otherwise, keep your head down and build.

There are exceptions to the rule, but those are the exceptions, not the rule.

The context: kudos to Yahoo for buying innovative startups like MyBlogLog, Flickr and Delicious -- but all 3 seem to have stagnated since the acquisition. In theory, large companies like Yahoo can bring greater financial resources -- and of course a larger audience. In practice, the "big company" culture often grinds things to a halt.