There are only a handful of Android devices currently available that are really ‘open’, those being the ADP1, ADP2, Nexus One and now the Nexus S. Devices Google classes as ‘open’ are ones where the user can freely change the build of Android that is on the device, eg. flashing a custom build like CyanogenMod or the like. This is done by having a bootloader that is unlocked, allowing these unofficial builds to be flashed onto the device. The Nexus One was the first to introduce the fastboot oem unlock command which unlocked the bootloader as well as voiding most parts of warranty, which is fine. Now the Nexus S takes this to a new level with both fastboot oem unlock and fastboot oem lock which will allow you to unlock the bootloader when you want to try out some new custom build then lock it when you no longer want to, perfect!
The problem with this is that the manufacturers aren’t really jumping on board, so Google is starting a little push to encourage them, saying that users need to be able to choose between security and openness.
Unfortunately, until carriers and manufacturers provide an easy method to legitimately unlock devices, there will be a natural tension between the rooting and security communities. We can only hope that carriers and manufacturers will recognize this, and not force users to choose between device openness and security.
I know everyone who has ‘rooted’ their device is in absolute favour of this, it’s just time for manufacturers to realise and keep up with the times.