Could Foursquare be the next acquisition on Yahoo’s shopping list? Maybe, maybe not, but All Things D’s Kara Swisher has just made an extremely convincing case that CEO Marissa Mayer is at least thinking about buying up the location-based social network.

Now Swisher gives a number of compelling reasons as to why Yahoo might be mooting such a possibility, including the fact that Mayer is such a big fan of the service that she once tried to buy it while she was still working for Google. Swisher also points to a recent talk in San Francisco, during which Yahoo’s CFO Ken Goldman dropped a couple of hints that Foursquare might be on the company’s shopping list.

“Now, when we find something interesting, we actually go and address it and acquire it, rather than thinking about it,” said Goldman. He added that Yahoo’s main interest right now lies in the “localization of the space” and finding companies “to help basically accelerate our progress… and continue to see the velocity of products in the mobile space.”

Given that Foursquare just so happens to be a specialist in localization and mobile spaces, it’s easy to see why Swisher has drawn her conclusions.

Such an acquisition would fit the bill for other reasons too – for one thing, Yahoo’s desperately been scrabbling around for ways to attract younger internet users, the so-called millenials, who generally avoid its services like the plague. The acquisition of Tumblr was made in a large part because of its youngish user-base, and the majority of Foursquare’s users also fall in the 20-something demographic.

Perhaps most compelling reason however is that, just like Tumblr, Foursquare has so far been unable to figure out how to turn a profit.

Why would this unprofitably tempt Yahoo? Simply because, Yahoo thinks it knows how to milk it. One thing that Foursquare has going for it that makes it EXTREMELY valuable in the eyes of an advertising agency like Yahoo (for that’s what it is really) is data. Lots and lots of data. And more specifically, location data, which can be used in any number of ways.

While Yahoo is likely to adopt the most direct and brutal method of making money on Tumblr, simply by loading it up with ads, it’s likely to take a different approach with Foursquare. The service already makes money selling its location data to Instagram and numerous advertisers, and given Yahoo’s stature it probably wouldn’t be difficult for Mayer to find more customers. Then again, it might just decide to take Foursquare’s location data and use it to enhance its own web search engine.

Just think for a moment – the combination of search, web content, blogging, location check-in, and photos (Flickr) would be hugely powerful, providing just about every aspect of the web that the average netizen delves into, right there in Yahoo. Foursquare may not amount to much on its own, but when combined with it’s other services, it might just be enough to tempt people to take a look at Yahoo again.