Staff and unregistered usernames are public usernames staff is public just for staff members there can use it got more features + unregistered is for all people they can use
If you like RD will publish your nice work(code or program) Just post them in RD boards code bank where thousands other programmers post there work and people will know ur work more
RD will advertise the code which you wish to show ( like a nice program such as ur site win) you can choose to make it available for all public or our good members who buy the code via RD$s from the shop ( its the forum currency with people earn from the boards)
making the safe mode will be the best solution for search engins + a way for other browsers by the time they catch with the technologies
but the free offer sounds very good ill pm u straight away! 
thanks again!