Yes i agree with this. And i think should they have come in a little later they would have missed the boat so in this regard they are lucky. In terms of how they have maintained and grew twitter to what it is now, that is skill.

If connection to the internet on mobile phones was mainstream at the time twitter started the SMS gateway would have been redundant just as it is right now.

I know alot of people who use twitter now and im pretty sure none of them know you can tweet via an SMS as most of them have twitter apps installed on their mobiles.