"I built the first version of Posse to help bands build relationships with their fans and to enable fans to get rewarded for helping to sell tickets. We integrated with all the major ticketing sites and we did more than $2 million in sales, but the model didn't scale.
"We ended up selling the platform to a major music festival in Australia that still uses it and we developed a similar community, but for retail."
Posse is a social search engine that helps people find the favourite places of their social network. The mobile app and site launched in March has signed more than 35,000 merchants worldwide, including 7000 New Zealand stores.
Users tell Posse what they want, such as "great coffee", "brunch" or "a gym" anywhere in the world and they will get recommendations from their "posse" of friends and local experts.
It covers most world cities, including Auckland and Wellington. The denser the population the better, so New York is a standout, says Campbell, who was in New Zealand for last week's Morgo conference.
A two-tier subscription model lets businesses send customers gifts and special offers. From next year, $50 and $100 monthly subscriptions will give stores access to additional features to help them build customer communities.
The business idea has attracted backing from a who's who of the tech world, including Google Maps founder Lars Rasmussen, Twitter's Bill Tai, Yahoo's Ken Goldman, Simon Rothman of eBay and New Zealander Tim Wood, founder iHug.
"They think it could be really big," says Campbell.
The expat Kiwi, usually Sydney-based, has spent time in Palo Alto and New York raising money.
"I get very excited when I go to a pitch. Pitching reinforces how good it is, it's always uplifting," says Campbell.
On the other hand, it can be a distraction from product development.
Posse has 11 staff in Sydney, where there is a pool of talented software developers, and five call centre and graphic design staff in the Philippines.
Campbell, the archetypal entrepreneur, has ideas for other ventures.
"I like starting businesses. I'm the kind of person who enjoys the early stages. If Posse takes off, I would find an experienced chief executive - that's not my expertise or passion," she says.
"I'm hoping in the next year or so to start something else. It's not about money, it's about coming up with an idea. I like building teams, getting people excited, creating a vision."
Top tip
Just do something - start. People spend too long planning - just write a plan and do it.
Best business achievement
Taking Evermore to success.