[Karunamon]

This is not an actual problem.

We disagree there. It's annoyance waiting to be solved. Here's a hypothetical, realistic interaction, and as a bonus, one that isn't any less useful due to the length limit:

    >>@friend: Want to catch lunch today?
    @friend: Sure, I'll set that up. Cya there!
    @restaurant Reserve a table for 2 at noon for Karunamon
    >>@restaurant: Confirmed, we'll see you at noon!
    @traffic: How's the traffic between here and @restaurant?
    >>@traffic: ETA 35 minutes, heavy traffic and construction along the optimal route.
    @restaurant Change that last reservation to 12:30
    >>@restaurant: Confirmed, your noon reservation has been moved to 12:30
    @uber Pickup my location to the closest @restaurant
    >>@uber: Driver is on its way. ETA: 5 minutes. Look for a grey Subaru, plates 1234-56.
    @friend: Catching a ride there, see you in half an hour!

And this is pure user interaction, which is the least efficient way to do things possible. If you can't think up a usage for a widespread pub/sub notification system, kindly get your imagination serviced.

As far as the limit, it's up for revision by the sound of things anyways - and keep in mind the original purpose of that limitation was so a tweet would fit into an SMS. If the limit is what you think breaks this idea, you've disqualified SMS by the same rubric.

[setpatchaddress]

You've just described the future of Siri, not the future of Twitter.

[Karunamon]

I don't know about you, but I don't want a separate walled garden of services based on the particular voice recognition app my phone uses (whether that be Siri or Now or Cortana or...). Using some other service that provides a sane communication layer that everyone already uses means that doesn't have to happen.