A startup Aaron Houghton envisioned to be a $1 billion second act to iContact has a new owner this week.

The serial entrepreneur sold BoostSuite, his labor of love for the past four-and-a-half years, to Raleigh-based digital agency Atlantic BT, which will begin to sell its digital advertising tools to mid-market retailer clients and others. The terms of the deal were not disclosed.

The decision to sell became obvious to Houghton and co-founder Daniel Smith, a former senior digital marketer at iContact, earlier this year. After several iterations of providing digital marketing services to small business owners, they eventually landed on a digital advertising tool that let 43,000 small retailers advertise to each other’s customer bases, which totaled 120 million monthly shoppers.

The results were staggering—they could deliver results 5.5 times the industry average and at 10 percent of the cost of advertising with Google.

But as traction built for BoostSuite’s tool, it became clear that mid-sized and larger retail customers would be necessary to build a large and sustainable business. They knew it was time to exit.

“Honestly, I wasn’t prepared to do what needed to be done, which was to take it to the mid-market—that’s not my skill set,” Houghton told me yesterday. “Building a sales team and pipeline is something I’m not interested in and other people are really good.”

Houghton took a fundraising approach to finding the best suitor for BoostSuite. Over the course of this year, he and Smith talked to 39 potential acquirers in the U.S. and Europe and narrowed down the funnel to Atlantic BT, which had served as a strategic partner over the last year.

In a news release, Atlantic BT CEO Jon Jordan said “The BoostSuite technology is unique and compelling in a marketplace crowded with mediocre marketing and advertising solutions.”

Along with its October 2016 acquisition of Blaze, a website content audit and strategy company, the firm is building a suite of online marketing products to offer its clients.

“We’re excited to begin writing the next chapter of the BoostSuite story as we put their unique technology to work for larger retailers and customers in the United States and around the world,” Jordan said.

This acquisition is markedly different than Houghton’s last. BoostSuite raised no outside funding other than an NC IDEA grant at its start in 2011, while iContact snagged $65 million from mostly institutional investors. Houghton employed just three full time and two part time employees while iContact had 250. And Atlantic BT is a local private company with a national client base, while Vocus was a publicly-traded company. 

Houghton always meant to build BoostSuite differently, and he also intended to leave the company before he’d be required to lead a large team again. He reflected on his first exit in a piece we published at the five-year anniversary of the deal.

On the phone yesterday, Houghton told me he’d retired, with a laugh. He’ll spend the next six months to a year meeting with the leaders of 100 startups in an advising or coaching capacity he’s calling micro-advising. His goal is to learn a lot during that time, and he assumes he’ll figure out what’s next as a result of those interactions.

He’s also getting started on a book project that recounts his journey managing stress and anxiety as a startup founder. It’s not a book about his success or his feats of entrepreneurism—he intends to offer startup founders 15 suggestions for dealing with the natural stress that comes from launching and building a venture.

It’s not clear if this will make the book, but a big piece of advice from Houghton is one evident in the recent exit—do the things you’re good at. Let others do the rest.