Note: Startups change frequently

...you don't get a memo that tells you that things have changed. If you did, it would read something like this: "Dear Eric, thank you for your service to this company. Unfortunately, the job you have been doing is no longer available, and the company you used to work for no longer exists. However, we are pleased to offer you a new job at an entirely new company, that happens to contain all the same people as before. This new job began months ago, and you are already failing at it. Luckily, all the strategies you've developed that made you successful at the old company are entirely obsolete. Best of luck!"

-- Eric Ries

There's lots of other great stuff on Eric's site.

Thanks to pphaneuf for the original link.