In case you see the Nautilus memory usage go sky-high in Ubuntu 10.04 Lucid Lynx (I'm not sure if this happens to the default Nautilus but it definitely happens on Nautilus Elementary - though it's not its fault) and you have the Unity PPA added, you can fix it by removing a single package:
sudo apt-get remove appmenu-gtk
Somehow the Appmenu-GTK package makes Nautilus (Elementary only?) use a huge amount of memory. Not only that but it seems it also causes some big CPU spikes.
When you stop an application (a process) on a Linux system, the kernel will free all memory reserved. A memory leak is when an (bad) application use more memory over time. In the present case, the application "appmenu-gtk" runs continuously in the background, and use more and more memory.
When you stop an application (a process) on a Linux system, the kernel will free all memory reserved. A memory leak is when an (bad) application use more memory over time. In the present case, the application "appmenu-gtk" runs continuously in the background, and use more and more memory.