I am confident that there will be a very active "Developer" community for this beast. If you have never been to xda-developers.com, I suggest you go over there and get familiar with it. A lot of those guys have accounts here and are more than happy to share when they cook up something good.
Technically, rooting your phone is possible by exploiting the Nand lock on the phone, which allows you to do a couple of things...
1) Make a complete copy of the phones files, in case you get a bad flash or for whatever reason need to restore the phone's original state. Do this right after rooting and do NOT delete this file.
2) It gives you permision to write over files HTC or VZW would rather you not. For example, you can rename cityid.apk to cityid.apk.bak so that the phone no longer recognizes it as an app and it doesn't show up on your phone (even though it is still "there")
3) Certain applications need "Super User" permissions, like Root Explorer, for example. So does Shoot Me and Titanium Backup. The SU app allows you to grant these apps super user permission.
4) It allows you to access all of the functions of the phone that have been locked down. For example, wireless teather. Instead of paying extra to unlock this feature, there are those who use other teathering apps (that need super user permissoin) to acomplish this without signing up for the service.
5) My personal favorite... Flashing ROM's and kernels. This allows you to re-image your phone and have a totally custom user experience. I know at least 50 people with DInc's, and not one of them is set up like mine. I am using a ROM ported over from the Desire Z, so it is sense 2.0 on a device that isn't "supposed" to have it. Way cool.
Keep an eye on this sub forum if you have the slightest interest in rooting and I know that there will be quite a few of us "Blazing the Trail" and sharing our tips and tricks for everyone else to have an easier and more positive experience than we did. Hope that answered at least some of your questions.