An improvement on my previous post:
Blockchain Username Constraints
This DIP takes a conservative approach to the characters permitted in a blockchain username. Namely, a subset of ASCII characters with no foreign language support at this point in time. Obviously, this may change in the future but it is intentionally taking baby steps first. In this spirit and as previously stated, I believe the period (".") should not be allowed in a username. While there is no mention of extending this namespace to DNS, I feel this is something we should be mindful of, and including a period at this early stage might prove problematic in the future.
Blockchain Username Pricing Model
I believe there is a good argument to be made for premium short blockchain usernames. Eighty percent of all english words are seven characters or less. Purely for reference and interest, you may wish to look at these stats for frequency counts: http://www.norvig.com/mayzner.html
Currently, a blockchain username can consist of 37 characters; A - Z, 0 - 9 and an underscore. The permutation count rapidly escalate, but of particular note, three and four letter words and abbreviations are both common yet limited in number. If we consider just letters and numbers (for easy recall), then three characters amount to just 46,656 permutations (36 x 36 x 36).
In the real world, promotional activities for businesses, charities, competitions etc make extensive use of short dialing codes e.g. "Send the text "PRIZE" to 123". Generally speaking, short codes are easy to recall. The average person can recall seven or eight objects after hearing them for the first time.
Given the above, I propose that a flat fee apply to all usernames with the exception of three, four and five character usernames; Gold, Silver and Bronze respectively.
The duration of a username lease is open to debate but I think the premium usernames mentioned above should allow for a minimum of one day.
The cost of premium usernames is also open to debate but my initial suggestion is:
: 0.1 dash per day
: 0.01 dash per day
: 0.001 dash per day
Fees shared between miners and masternodes.
The high price to entry raises the stakes in a very neutral way i.e. big brand names (or high risk scammers) can afford to lease short usernames. Short premium usernames discourages hodling on a long term basis and encourages entrepreneurism.