Thermal Creep

Google told me that :
http://www.cfm.brown.edu/people/beskok/creep.html

If I am looking at this correctly in an IT related situation, Thermal Creep means that your system is slowly gaining heat, or transferring heat to another part or system.

If you have a thermal problem with a PC, or in a server room, you need morecooling.

Many PCs are set up with only exhaust fans, and no intake fans. This can lead to areas inside the case that have little or no air flow.

I set up my systems with positive air pressure. The intake fans have at least 10% more air flow than the exhaust fans.
If you install filters over the intake fans, you can keep most dust out, which also helps.

Chas