[Best practice] Heavy background tasks?

[eluser]Clooner[/eluser]
[quote author="jedd" date="1239119207"]Depending where you are in the development cycle, the option of de-normalising your primary database may exist.[/quote]

I am still at the proof of concept phase. The development will start next month. I have the system working already but I'm sure it will fail when the load will get to high. De-normalizing is actually a really good idea and will get rid of a lot of calculations, difficult queries. There are some down sides to this. Just have to figure out what they are...