One of the most lucrative markets in the consumer internet has been online dating. And one of the most successful players over the years has been Match.com. It’s not difficult to see why: plenty of people are willing to pay for a chance at a date and Match.com has been successfully charging for them for more than a decade.

But business isn’t so easy today. Newer competitors, many of them free, have gained traction, and one, Plentyoffish, is, according to comScore’s numbers, the most popular dating site in the world. Apparently Match.com doesn’t like that.

The company questions many of the claims he makes on the Plentyoffish site. For instance, Match.com finds it hard to believe that Plentyoffish members will go on 18m dates this year, was responsible for 500,000 relationships in 2007 and receives 20,000 signups each day.

So Marshall Dye, Match.com’s general counsel, sent a letter to Frind telling him so. “Based on my knowledge of the industry, these claims cannot be supported and are misleading and/or false,” he writes. And then he makes a bold demand: get rid of these claims, unless you can provide evidence that they’re real. Not comfortable doing that? Match.com will sign a confidentiality agreement to get the proof.

I for one have no idea whether or not the claims that Frind makes on Plentyoffish are legitimate or not, but Match.com’s approach to competition is, for lack of a better word, strange. For starters, it’s not clear that Match.com even has a right to demand that Frind ‘put up or shut up‘. If claims made on Plentyoffish are misleading or false, one would assume that a government agency, such as the U.S. Federal Trade Commission or Canada’s Competition Bureau would be a better place for Match.com to lodge a complaint.

But even then, trying to rat a competitor out to regulators usually isn’t a very productive long-term business strategy. Sure, you might get lucky and hurt the competitor in the short-term, but when your business is at risk of falling behind due to broader market forces, it’s probably far wiser to focus on what counts: product and innovation.

Here, it seems apparent that Match.com is worried about its market position and that Plentyoffish’s success is bothersome.

Perhaps there is a legitimate point to be made about some of Plentyoffish’s claims, but it’s unclear what Match.com stands to gain from threatening Plentyoffish’s owner. That certainly isn’t going to help it compete more effectively against newer competitors, many of whom are trying to build businesses around ‘free‘. And even if Match.com was successful in getting its rival to remove some of its claims, it’s hard to believe that would have any impact on Plentyoffish’s usage.

The bottom line is that competition is rife in most online markets, especially on the consumer internet. At some point, businesses need to make a decision: are we going to worry about something we largely can’t control (what the competition is doing) or are we going to worry about something we can control (what we’re doing?). The answer should be an easy one.

Photo credit: pedrosimoes7 via Flickr.