1. Rooting is like being given the Administrator account to a windows computer. Without it, you are limited in what you can do.

2. Having root access means having access to things in our system that your phone manufacturer doesn't really want you to have access to. This allows you to do things like overclock your processor, or delete system apps or "bloat" as we call it.

3. Both root methods I personally have used are so easy I find it impossible for anyone with half a brain to mess them up. That being said, while the root process is unlikely to harm your phone, what you do with your new found root access CAN.

At this point in time there is no SBF (a recovery option) for the Bionic available. So while you can root the device. If you delete the wrong system app and break something, your phone is going to be a nice paperweight for a while.

 

Yes, it currently requires a computer. You will be better off making future threads in the Droid Bionic - All things root forum in the future. Just a heads up, because that is where all the real phone geeks are lurking

[ROOT] Droid 3 root instructions (One Click added for Windows/ Linux/ OSX))

The second post in that thread details a step-by-step guide on rooting any motorola phone on gingerbread. It has been tested and works on the Bionic.

You do this at your own risk however. As I have stated above, if you break something your warranty is voided and there is no way to fix it currently.

 

There are some handy root apps like screen shots, ad blockers, and reboot widgets. From there it gets more dangerous like removing bloatware, theming, and rom'ing. Rooting allows outdated phones that are end of life to receive Android updates from the developer arena. My old Eris is running 2.3.5 which is a newer version of Gingerbread than the Bionic has.
Wifi tethering is the contentious root use. Basically you could pile 255 additional devices onto Verizon's network all sucking down LTE goodness. Not a cool thing to do to a wireless carrier. This is why you will see many arguements floating around as to whether it is right or not.