random applications start chewing memory

This has happened to me twice in the last 2 days now, although i'm still not sure if the two occurrences are actually related.

yesterday when i plugged in a USB flash disk the whole computer basically froze up. I managed to get the system monitor up while it was grinding away on the harddrive and found it had consumed all my memory and started swapping EVERYTHING. The culprit was tracker-indexer, multiple copies of which had spawned, one was using over 1GB of memory.

I contained the situation, managed to kill the process before it completely chewed the pagefile.

Anyway tonight i was starting my computer, started skype, prism, and eclipse 3.2 all at the same time. Same things happens. This time it's eclipse that ramps up to over 1GB of memory usage in less than 10 seconds, causing Ubuntu to start swapping furiously.

Like i said i'm not even sure if these two occurrences of the same problem are related, i'm not schooled well enough in operating system application launch mechanics, so i don't know if it's a linker problem, program-specific problems, or what.

If you need any logs i'll have a go at digging them up, but i'm a bit of a Linux newbie (4 months and counting).

My system:
Core 2 Duo T7200 2.2GHz
2GB DDR667
160GB 5400rpm sata disk
Nvidia Geforce 8400M G
(laptop)

Running Ubuntu Jaunty (9.04)