In response to a few tips Alex Netkachov recently posted about micro-optimization, several other developers in the PHP community have written their own responses:

• Maggie Nelson - Optimization Woes
• Sebastian Bergmann - Do Not Micro-Optimize
• Padraic Brady - Can't see the forest for the trees? Quit micro-optimising and try again
• Stefan Priebsch - The five immutable rules of optimization

Alex's tips, which have the potential to be slightly helpful, can also give a false impression that they will make a large difference in an application and could make a developer write code differently (pre-optimization) to try to use them.