Constant Contact, a well-known entity in social media marketing and email marketing, has just added a new area of expertise: storefronts and discovery tools for local businesses, via the acquisition of SinglePlatform for $65 million.

Since Constant Contacts bread and butter are small and medium-sized businesses (SMBs), the acquisition makes perfect sense. In addition to its existing suite of “engagement marketing” tools, Constant Contact will now be better prepared to offer their SMB customers services specifically tailored to helping them reach their own local markets better.

SinglePlatform helps businesses publish their information — such as a menu, special discounts, and photos — to review websites, city guides, and other first-stop destinations for consumers doing their homework. It’s a more passive form of marketing, almost akin to SEO; but it’s important for local businesses.

“There are hundreds of online and mobile sites that consumers use to find local businesses and make purchase decisions. It’s literally impossible for time-starved small businesses to keep up with all of them,” said Constant Contact CEO Gail Goodman in a statement on the acquistion.

“Almost 50 percent of searches for local businesses happen without a specific business in mind, so it’s absolutely critical that small businesses are listed everywhere to ensure they are found when and where consumers are looking.”

Post-acquisition, basic listings on SinglePlatform’s publishing network of sites and mobile apps will be free from Constant Contact. SinglePlatform will continue to sell its digital storefronts, which let SMBs add videos, images, and menus to those basic listings.

In addition to the $65 million purchase price, Constant Contact kicked in an additional $5 million in cash and equity to keep existing Singlelatform team members on board. Also, if SinglePlatform meets certain revenue goals, Constant Contact has earmarked an extra $10 million to $30 million for special compensation.

SinglePlatform was founded in early 2010; the team raised a total of $4.45 million in two rounds of funding from such entities as First Round Capital and DFJ Gotham. The deal officially closed June 12, 2012, making SinglePlatform a wholly owned subsidiary of Constant Contact.

“The internet is shifting from a listing directory to a discovery engine,” said SinglePlatform CEO Wiley Cerilli (pictured) in a release today. “The first step is making sure your listing is available wherever people are searching. The real magic happens when rich business information… is delivered at the moment that people are making a purchase decision. SinglePlatform’s Digital Storefront is designed to do just that, getting small businesses in front of more people with the type of information that drives new customers and increased sales.”