As Google played April Fool Day prank with its users Twitter has also played prank and they had announced that they are going to shift to two-tired system in which they will introduce new service Twttr which will be free and Twitter will be chargeable at the rate of $5.
On Twttr users can only use consonants and on full version of witter you can use vowels and get one extra character to write on your Tweet, means 141 characters.
As per Twitter :-
“We’re doing this because we believe that by eliminating vowels, we’ll encourage a more efficient and “dense” form of communication. We also see an opportunity to diversify our revenue stream”