I posted this in another forum. I though it might help explain things.
Let me try to make some basic comparisons using Windows OS as an example....
Rooting is simply getting access to the device's system as a "Super User" or SU. Think of it like an Administrator vs regular user on Windows. There are a lot of rudimentary things in Windows that you can only do as an Admin. Getting root access on a phone does allow you to add, modify, and delete things that a regular user cannot do. This will probably allow you to modify the theme to some extent, over clock the processor, add "unauthorized" programs, etc, etc, etc.
Having unrestricted access to the bootloader allows a user to load completely new ROMs. It would be like a Windows XP user installing a new OS like a super customized verson of XP, or upgrading to Windows7, or moving to Linux, or any other OS, etc, etc, etc.
The (suspected) problem with the Droid X bootloader is that it will only accept digitally signed ROMs from Motorola. So if Moto releases Froyo (which they have already annouced), then you can upgrade to that without problems (like going from XP to Windows7). What you cannot do is use the bootloader to install any other ROM that hasn't been officially released from Moto for the Droid X.
Is it something to worry about? I guess that depends on what you planned to do with your phone. If you are a "stock" phone kind of person, then you have nothing to worry about. Even if you wanted the ability to root and play around with some changes, you probably have nothing to worry about. But if you are a hard core "tweaker" that loves to push the envelop, or if you are worried about Moto dropping support for the Droid X (it will happen one day) and you want the ability to use customized ROMs, then this probably isn't the phone for you.
Hopefully this helps explain a little better the situation we face with the Droid X (at least as we know it today).
The other thing is that I wanted to clarify what the "digitally signed" bootloader means. Sometimes I've said things that are not really that clear....
A bootloader can be designed so that it checks and only allow properly digitally signed ROMs from being loaded. Some bootloaders do not have this "digitally signed" requirement and will load up any ROM. It is expected that the bootloader on the Droid X is one that will only work with digitally signed ROMs with Motorola's digital signature on them.
This means that only official Droid X ROMs released by Motorola itself will work on the device.
I hope that helps.
