Late last week, Microsoft took a step anyone who follows Xbox Live has known would come eventually. The company announced that on April 15, it will end support for online play of original Xbox titles.

While it would seem that Microsoft, a company with pretty deep pockets, should be able to afford to keep the old black box online indefinitely, the company acknowledged back in August that the original Xbox was the reason friends lists on the Xbox 360 are capped at 100. Apparently, back in the days of Microsoft’s first console, 100 was deemed a sufficient cap. But with the rise of online social networking, the creation of Gamertag aggregators and integration with Facebook, 100 friends is a pretty small number for some folks.

Because the Xbox 360 and Xbox both use Xbox Live, and because Microsoft can’t issue software or title updates for their original console, the Xbox 360 was essentially locked into the limitations of Microsoft’s previous console until the company either ended Xbox Live support for its first console, or came up with another solution, such as partitioning off original Xbox gamers in their own corner of Xbox Live. Given the ability of original Xbox gamers to play that game’s most popular title, “Halo 2,” with gamers on the Xbox 360, the solution might have been complicated.

Since the news about ending Live support for original Xbox titles broke, there’s been a predictable outcry on the Internet from console gamers who think they should be able to play these legacy games online for as many years as they want to. But how many people are still playing Xbox titles online? After all, “Halo 2” is now more than 5 years old.

As a commenter on Joystiq pointed out, the developer of the “Halo” games, Bungie, can help answer that question. Over on Bungie.net, the company tracks how many people have played each of its games online in the previous 24-hour period. I kept an eye on the stats for “Halo 2” throughout the weekend, and the number consistently hovered in the 4,000 to 5,000 player range. That’s not a heck of a lot. For comparison’s sake, “Halo 3” has logged roughly half a million players in the past 24 hours, while “Halo 3: ODST” has around 40,000 players. (The “ODST” numbers are noticeably lower because it has fewer game types, as well as limited online matchmaking that forces you to play with friends.)

In other words, “Halo 3” players could outnumber “Halo 2” players by a factor of about 100 to 1. And unlike “Halo 2,” the third game in the series isn’t even the most popular title on its respective game console. “Call of Duty: Modern Warfare 2” was king on the 360 last week. And Microsoft has said the number of Xbox Live accounts numbers somewhere in the tens of millions.

In other words, a few thousand original Xbox diehards have likely been holding back bigger friends lists, as well as more advanced social networking features such as the ability to create groups and clans on Xbox Live. While Microsoft hasn’t announced any specific plans, you can bet they wouldn’t take the risk of alienating some of their longest-running, most loyal customers if something big wasn’t in the works. We may find out as soon as Thursday, when Microsoft’s X10 media event in San Francisco will shed some light on plans for the Xbox 360 in the coming months.

As for these die-hards, it’s too bad they’ll be losing access to online gaming. (The offline portions of original Xbox titles will still work, and you’ll still have the ability to hook consoles together for System Link gaming, the Xbox equivalent of a LAN party.) But if there really, truly are only a few thousand left, Microsoft likely judged that the cost of appeasing this small minority wasn’t worth the money these gamers would’ve paid in Xbox Live membership fees.