getaccountaddress 0 (what does this do?)

[libertyzeal]

I've been reading several of the masternode setup guides, and the instructions don't go into any detail on what a lot of the commands actually do, for example after running "masternode genkey" we are asked to run getaccountaddress 0.

I'd like to know what is the 0 account, as opposed to the default account "", etc? Is this some special syntax rather than just using an arbitrary string for the account name?