Over the past two years, there’s been a dramatic decline in email usage among people aged 12-24; they’ve largely turned to text messaging (SMS) and posting to Facebook instead.

This kind of seismic shift in communication strategies along generational lines signals the need for innovation and adaptation, of course, and down at Y Combinator (YC) this spring, there’s a startup called SendHub that is poised to help.

The problem with SMS is that it’s hard to send a message to more than one person at a time, so SendHub has developed a solution for that problem, making it easy to send the same message out to groups of people simultaneously.

“You can send one message to everyone from anywhere,” says co-founder Ash Rust. “These can be to or from any browser extension or cell phone and to all your social networks.”

Creating a group at SendHub is easy, based on accessing a common keyword, and delivery of messages can be scheduled for any point in the future.

So, for example, YC is using SendHub to remind its current class of entrepreneurs to attend its weekly dinner at 6:30 on Tuesday nights. “Within 15 minutes of sending out that reminder, the room fills up,” says Rust. “Otherwise, it would be easy to forget, because we’re all heads-down trying to develop our products during the three months we spend here.”

It’s easy to envision some of those who will appreciate SendHub’s new service. Teachers can use it to contact their students about homework, tests or schedule changes; health-care clinics can remind patients about appointments; coaches can remind players to get to practices and games on-time.

In fact, anyone who tries to communicate with teenagers these days knows that email is pretty much a non-starter, more likely to fail than succeed, where a text message buzzing on their cell phones is much more likely to catch their attention and provoke a response.

In preparing for a post-email world, the SendHub team is looking at a former YC startup, Dropbox, as a model for how to build out their service.

“We want to be the Dropbox of SMS,” says Rust. “Dropbox just does file synching and it does it really well. Why can’t there be something as easy as Dropbox for consumers for messaging?”

Rust says SendHub is “committed to the social good” that can result, so the basic service is free for the first 1,000 messages to a group of up to 50 people per month, with premium options priced above those levels.

“We are finding that businesses are interested in using it for communication problems they already have,” he explains. "Such as companies on the east coast that distribute their goods to 3-4,000 stores, with the deliveries over 5-6 day period.”

The startup is starting to see another use, as well, and that is by political organizations and campaigns. It's not hard to imagine “get out the vote” efforts via SendHub coming soon this election year.