Though doubles of numbers are easy to remember, they do require more keypresses than numbers that alternate. So for instance 1313 is easier to type than 1331 or 3113.
In the same way 131 is better than 311 or 331.
My RAZR already has predictive input on its browser, but it doesnt predict extensions. Alot easier than a .mobi key and the bare minimum would be it predicting .mobi for instance, if you type domain.m
Then to add a .mobi extension to a domain, its only three key presses. 1, 6, <right arrow>.
In the same way 131 is better than 311 or 331.
My RAZR already has predictive input on its browser, but it doesnt predict extensions. Alot easier than a .mobi key and the bare minimum would be it predicting .mobi for instance, if you type domain.m
Then to add a .mobi extension to a domain, its only three key presses. 1, 6, <right arrow>.