We can officially call Windows 7 a bona fide hit, according to data compiled by ZDNet’s Ed Bott.

Almost a year after the operating system’s release, we can look back to see just how well it did — and the numbers look good. A Microsoft exec revealed to Bott this past spring that it had sold 100 million Windows 7 licenses, and that number jumped to 175 million in a July quarterly earnings call. The company expects to sell 350 licenses by the end of the year — or about 30 million copies per month globally.

Strangely enough, Microsoft hasn’t really publicized the success of Windows 7. Apple, meanwhile, gave up on its “Get A Mac” ads, featuring Justin Long and John Hodgman, shortly after Windows 7′s release. With so many positive initial reviews from journalists and users alike, Apple would have seemed out of touch if it continued with its mocking ad campaign.

This is one of those situations where Microsoft’s marketing ineptitude becomes clear. In late 2008, the company tried to revive its lagging image after the failure it experienced with its Vista product with a series of irreverent ads starring Bill Gates and Jerry Seinfeld (which director Michel Gondry was reportedly involved with), but it killed the project after a poor public response. As a volley against Apple’s then-ubiquitous ads, it was also a failure.

Now that Microsoft actually has a legitimate success on its hands, it doesn’t quite know how to sell it. We’re still seeing the same “Windows 7 was my idea” ads that have been around for months and that try to convince viewers that the operating system is worth their time. Perhaps in the near future, we’ll see ads more along the lines of “We’re kicking butt, and here’s why.”

Bott also figures that Windows 7 has a good shot of knocking out Windows XP as the preferred corporate operating system in the next few years. “Today, roughly 70-75% of corporate desktops are still running Windows XP. If enterprise adoption rates for Windows 7 continue at the seemingly slow pace of 1.5% per month, Windows 7 will probably overtake XP in corporate installations by the end of 2011,” he writes. “If that rate picks up even slightly, as it appears to be doing, then there’s a good chance that XP will hold a single-digit share of corporate desktops when it’s officially retired in 2014.”