The Mars release of Eclipse IDE introduces the Oomph installer to manage Eclipse setup. It has an advanced mode where you can select a directory as "Bundle Pool", create "Agents", etc.
So, what is the concept behind all that and wherein lies the benefit?
"You can choose ‘bundle pool‘, to share Eclipse plugins between installations. This means that if you install another package, all the common bits will be shared."
Also, Eike Stepper says:
Oomph's underlying infrastructure supports bundle pooling for all aspects of the installation (and, optionally, even of the target platform), i.e., when installing multiple products using Oomph or when provisioning multiple target platforms, the installations and target platforms can share all the common bundles and will download each bundle only once. This dramatically reduces disk space as well as speeding up installation and target platform provisioning time. Of course one can disable bundle pooling to produce an installation exactly like you get with an unzipped package download. You can also see there is a dialog to manage the bundle pools.