Twitter Buys Personalized Email Marketer RestEngine To Deliver Best Tweet Digests

Twitter has just finalized a deal to hire the team and buy the technology of RestEngine, a personalized email marketing service, which could help Twitter deliver email digests of great tweets you’ve missed. The deal fits well with Twitter’s recent talent acquisition of Summify, which creates these kinds of personal news digests. RestEngine had been powering re-engagement emails for social game companies like Crowdstarthat enticed users to start playing again by telling them what their in-game friends had been achieving.

Three of four founders will be joining the flock, and the company’s technology will come along with them. RestEngine’s founder Joe Waltman called this is an acquisition since Twitter’s gaining both employees and tech, though Twitter views it as an acqui-hire. Co-founder Joe Waltman won’t be moving to Twitter as he tells me his entrepreneurial spirit is too strong and he’ll be working on new projects after a vacation.

It looks like Twitter’s got a plan to get more of its inactive users tweeting again.

Here’s the full-statement RestEngine is showing on its homepage:

“We’re very excited to announce that the RestEngine team is joining the Twitter flock! Just over two and half years ago we founded RestEngine to help social app publishers send targeted one-to-one emails based on a subscriber’s social graph. It’s been an incredible journey where we had the opportunity to work with some of the leading social app publishers. With our customers, we’ve iterated on our social marketing automation platform while defining a new set of best practices for this brand new world of outbound social marketing. We’re thrilled to now focus our email skills and marketing automation know-how on a much larger scale at Twitter.”

The note was signed by all four team members @jaberant (Josh Aberant, co-founder), @joewaltman (Joe Waltman, co-founder)  @Soren_Berg (Soren Berg, developer), and @mikelinca (Mike Lin, web/UI developer)

As for details of the deal, Waltman tells me it was signed two weeks ago but RestEngine just got confirmation that everyone who wanted to join Twitter would be hired. He wouldn’t tell me what Twitter paid for the boostrapped company, but these deals are typically structured to give anyone joining some cash but more equity in order to retain them, while paying out a mid-size lump of cash to founders who are going their own way. Waltman says his engineers are very excited about the move, especially because they hadn’t worked at a big company and are looking forward to the mentorship and advice Twitter will give them.

As I wrote when I first covered RestEngine back in July 2010, the company helped Facebook game companies in particular to deliver high open-rate emails. They’d include a recipient’s score, energy level, which friends were playing, and their next in-game tast to create a sense that a user was already invested in the game, and they’ll have plenty to enjoy when if they return. With time it expanded from serving game companies like Kaboom and RockYou to serve other web services like Ustream and SocialWeekend.

I’d heard Twitter was interested in surfacing the best content from a user’s network, but didn’t want to move away from the unsorted firehose stream it’s known for. Summify and RestEngine could help it accomplish this through the email medium rather than cluttering Twitter’s clean interface. Those emails could show the most retweeted, @replied, or favorited tweets by people you follow.

Until now, emails from Twitter have mostly been dry “this person followed you” alerts, but soon they could become something you actually want to open. Twitter now has over 140 million active users, but over 500 million registered accounts. RestEngine’s emails could bring some of those birds back to life.