Get ready for the first concrete news on the next version of Microsoft Windows, the next edition of Visual Studio, and what could very well be the first Windows product to serve applications "in the cloud." PDC is all this week.

LOS ANGELES (BetaNews) - It's apparent even from before the get-go that the theme of this year's Microsoft Professional Developers' Conference is winning back the marketing momentum, and bringing back developers' enthusiasm in Windows as a brand. Certainly many of them are already enthusiastic about the technologies they work with -- ASP.NET AJAX, Silverlight, C#, LINQ, the new dynamic languages like F#. But in the last round, that enthusiasm didn't translate into Vista, the consumer brand.

In other words, regardless of where developers have stood with Windows technologies -- and for many of them, it's not all that bad a place -- it's in a different world from the broad base of users who find Vista, with its frequent prompts for user consent and its infrequent compatibility with device drivers, generally irritating. Relatively few actually take the Apple ads' suggestion and cross the divide into the Mac realm, but quite a few of them share their sentiment and agree with their message, and that is a serious political problem for Microsoft.

If you're a political candidate, even if you're aligned with the majority in power, if you're several points down in the polls, you won't get far ahead by continuing to align yourself with the policies of the past. So the message of this year's PDC is, "Change is coming."

At the Sunday afternoon "pre-conference," during early registration and outside Microsoft's all-day educational seminars, the buzz in the hallways among the first to arrive is something that can basically be called the "Mary Jo Theory." Based on a hunch relating to a notice to hardware developers a few weeks ago urging them to attend next week's WinHEC conference here in Los Angeles, stating it would be the last one before Windows 7 is released, ZDNet blogger Mary Jo Foley has advanced the theory that the final Windows 7 could be released to manufacturing during the first half of 2009, rather than the second half as most believe, or the first half of 2010 as some manufacturers have speculated.

If the "Mary Jo Theory" plays out, that may not exactly be good news for developers. They're already getting betas of Visual Studio 2010, which many will use (against Microsoft's advice) as a production platform for building applications for Windows 7. A 2010 release date would mean VS 2010 is "in sync" with Windows 7; if Win7 is actually due earlier, then the production platform of choice should probably remain Visual Studio 2008.

More importantly, it gives developers less time to fulfill what their employers perceive as "due diligence" with the new operating system. A full Windows beta period is very important for a large production team. If Win7 is really due as soon as next May, then it could mean either of two things: 1) the next version really is, like it says under the hood, Windows 6.1, a mere window dressing of Vista and not really worth investing time to build upon as a separate or evolved platform; or 2) Microsoft is accelerating the development period in order to ramp down Vista's marketing life cycle as soon as possible.

Either possibility, therefore, isn't actually all that desirable from the developer's point of view. Keep in mind, PDC isn't produced for the consumer. Its core audience is smaller than TechEd, made up of more corporate developers and fewer new students to the craft. These developers often represent Microsoft's major partners, who produce the third-party software whose success in the market will, in the end, actually determine the relative success or failure of Windows 7.

Now, by contrast, next week's WinHEC audience will be comprised of hardware manufacturers and OEMs. Many of them may actually be thrilled by any news, if it does come this week, that Windows 7 would be an H1 2009 product, well within the back-to-school timeframe. But there will be a substantial plurality of software developers who would be pleased enough if the release date were something more like September, and if Windows 6.1 really does represent a substantive enough change to warrant the Windows 7 moniker.

Next: What should we expect to see this week...