pf » Premature optimization is the root of all evil

That's a quote from Dare Obasanjo at Microsoft who worked on the MSN Spaces project.

Dare's point is that even the big boys have trouble scaling their applications, MSN Spaces grew much faster than Microsoft had anticipated:

I never expected that we'd grow to be three times as big (as livejournal) and three times as active within a year. We've had our growing pains and it's definitely been surprising at times finding out which parts of the service are getting the most use and thus needed the most optimizations.

He also points out that Google has the same problems, Google Analytics was unusably slow when it first launched and the stats are still at least a day old before you can view them.

Dare wrote this peice in response to 37Signal's recent article: Don't Scale: 99.999% uptime is for Wal-Mart - also a good read.

So follow best practices, write code that is easy to maintain, don't go out of your way to optimize anything while during development. Once you have actual users you can get a better idea of what areas need optimization, and spend your time on more important things.

I also recently found a post in my archive called Over Tweaking on this subject that is worth checking out.