Last we heard from Shoutlet, the company had raised $15 million to make social media marketing easier. Today, Shoutlet is furthering its cause with the addition of Foursquare to its suite of supported social networks.

Shoutlet makes it easy for companies to run their own social marketing campaigns on Facebook, YouTube, and Twitter. With the inclusion of Foursquare, Shoutlet becomes a more valuable tool for businesses looking to get more information on who is visiting and checking-in.

“There’s a hidden goldmine of activity on Foursquare that marketers are eager to tap into,” Shoutlet CEO Jason Weaver told VentureBeat.

Using the new Foursquare integration, marketers will able to keep a close eye on key Foursquare metrics like check-ins, tips, and mayorships. That information can then be used schedule and run better-researched promotions and campaigns directly through Shoutlet.

While that’s helpful on its own, it’s made more so by Shoutlet’s capability to tie the Foursquare actions into other social networks. So, marketers can, for example, tweet out promotions when a certain number of customers check-in. It’s a powerful, multilayer tool that Weaver says is going to be invaluable to marketers.

“It’s one of the most exciting integrations we’ve done,” Weaver said.