Named accounts enable users to easily remember and communicate their account information. We don't use IP addresses to browse the internet or numbers to identify our email, so why shouldn't we have human-friendly account names for our blockchain transactions?
Every BitShares blockchain account is assigned a globally unique name that can be selected by its creator. There are many uses for named accounts beyond security and simply being an alias to a set of dynamic account permissions. They can be used as user logins or even mapped to your domain name. Named accounts are also transferable, which means a name can become valuable in its own right.
BitShares blockchain defines a simple algorithm to determine the fee it charges to reserve a new account name. Names that contain a number, are longer than 8 characters, or contain no vowels are essentially free. Otherwise the name is priced according to its length. BitShares has the power to adapt to market demands by allowing Delegates to propose a different fee for each length.
A BitShares account can be transferred by updating the permissions used to control it. However, the semantics of transferring an account are slightly different in the context of a web-of-trust. Users need a means to update their keys for security purposes while maintaining their standing in the web-of-trust. In other words, users must be given a way to explicitly transfer an account name to a new user while breaking any liability for how the account is used in the future.
When a BitShares user transfers an account name to another user, they use a special transaction that clears all of the links in the web-of-trust. Both the buyer and the seller are protected by this fact, because simply updating the key that controls a named account does not signify a legal change in ownership.