The important thing about EOS accounts is that they have a unique human readable name. At this point in time account names must be 12 characters long and may only include the characters 12345abcdefghijklmnopqrstuvwxyz. Part of the reason for this is to prevent "name-squatting" from occurring in the early stages of the EOS mainnet launch. Unfortunately these limitations don't make for the prettiest names - no sweet.rose allowed.
The owner of these premium names would then be able to generate new accounts that can be shorter (but not longer) than the 12 character limit, and may include a "dot". The owner of .mydapp could create user1.mydapp, iam.mydapp, whatever they wish. These accounts are unable to be deleted and may be given away at the discretion (or for the correct price) of the owner of the premium name.
Mechanisms are being developed starting from Dawn 4.2 that will allow anyone to begin bidding for a name they feel will be valuable as a premium name through a built-in auction. The important notes at this time are:
* Premium name bidding does not begin until 14 days after the mainnet unlocks. (The mainnet will unlock and officially reward block production once 15% of the total EOS supply has been staked and voted for block producers).
* Any name may receive bids by anyone
* Each consecutive bid must increase by 10%
* Only one name will be awarded each day - the name awarded is the one that has the highest bid of all names as of that day.
In addition to the competition by block producers to receive votes, for EOS to be used to stake for Bandwidth and CPU, to purchase RAM on a Bancor market, a whole new world of name auctions and name market places will appear. It is anticipated that the first several days after the name auctions become active we will see Top Level Domains bid on rapidly. Early adopters will be rewarded by bidding on names early in the first days before competition becomes even more fierce. Name market places will arise to sell specialized account names.
While remaining subject to change the current model would indicate that niche and specialized Dapp names may have to wait significant time before their preferred premium names will be the "highest bid" while fierce bidding is occurring. We may see cases where certain groups may place very large bids on personal premium names just to force them to the top of the highest bid rankings out of impatience or as an attempt to secure their premium name.