Originally Posted by lanceot
I'm new to Android, so by "rooting" we are only talking about access to android marketplace and more apps correct?
Android is basically Linux
Rooting your device means giving yourself root, or superuser (admin) access, giving you access to system files and the ability to change things that normally are marked read only.
This allows for removing "pre-installed" applications (called by some people "bloat-ware", because they bloat the system.), installing other applications (for example, although members of this forum figured out how to "side-load", or install without a market, some of the Google apps, the "Google Market" requires an entire framework which needs root access), and making changes to the system in ways that generally void your warranty (but can sometimes speed things up and make the device do things that no one expected it to do).
"Rooting" is also the first step (but only *one* of many) toward installing custom versions of the Android operating system (or "ROMs").
It's kind of a big deal, and the ability to root makes the device just *that much* more appealing to people who like to tinker.