What is Location field in Active Directory used for?

Is the Location field in Active Directory used for anything other than listing where objects are physically located?

I am interested if this is just a user friendly field to help people find printers etc. or if a change to this field will have some other effect.

Exactly that - the physical location of the object. Changing it won't affect anything else unless an external system uses or updates it. For example, in large enterprises, attributes like this could be populated from and synchronised with an asset tracking database using an IdM system like MS ILM/FIM.

Location tacking of printers is cool for everyone if it's done right. In Windows 7 your "find printer" view is auto filtered to your physical location. This is part manual setup, part IP subnet.

http://technet.microsoft.com/en-us/library/cc780327(v=ws.10).aspx

Like most user/admin-populated AD attributes, it's used for whatever the heck you want to use it for. Generally, that would be for the physical location of the object, as Chris McKeown points out, but you could use it for anything you wanted, and there might be some value in doing so if you're a small company with everything in the same physical location, given that, by default, Location is displayed more prominently than CustomAttribute8 and the like .

I saw an AD environment a little bit ago where the sysadmin used it to somewhat subtly insult the users with locations like in the clouds, lost in shipping, lodged in Cologne, and so on (think user's head is...), so the possible uses really are only limited by your creativity (and perhaps, level of malice).