An interesting scenario:
Given that Microsoft has funded ActiveState for a while, and now, now ActiveState is popular, the following conditions apply:

• A large quantity of pure Windows developers have now at least heard of Perl.
• A significant amount of them will now be using Perl.
• Many companies using Window based servers may well be running all their processes using Perl.

Given the above conditions, it's reasonably safe to assume the following:

• Of the many pure windows developer, a portion will at some point use Perl to see what the fuss is about, and because many companies now ask for it as a skillset, due to it's popularity.
• Of those using it, a majority will likely use it for writing utility scripts, with some coming to use it exclusively.
• The companies that have invested in developing systems in Perl will have invested a significant amount of time and money into the scripts they own and run.

Now, if Microsoft rocks the boat and states that Perl is not to be installed/finds some way to break the way that Perl operates on Windows in a patch, it is feasible in a good many cases that the following will occur:

• Of those Windows only Developer follow the urge to learn Perl, they'll likely find notices that it now only runs on non windows platforms. This will expose these people to the concepts of other platforms, where possibly otherwise they could have more easily ignored them.
• Of those that use Perl, if they need to keep using it safely, they may have to create a quick dual boot on their machine/commission a cheap machine to run an Open Source OS (such as Linux/FreeBSD etc), increasing their exposure to Open Source, and the community at large.
• For the companies that have heavily invested in Perl, it may be cheaper for them to ditch the Windows boxes in favour of an Open Source solution, on which the systems they have developed will continue to work safely.

As far as I can see it, Microsoft are trying the old trick of 'forcing the issue' and trying to break the competition.
However, in this case, the competition can be tried for free, is already established, and heavily invested in.
So, it's feasible that MS, in their hurry to try and shut away the Open Source phenomenon, they are in fact forcing people to consider it as an alternative.
I'd find it very funny if that's how it worked out. :)
As an aside, in a sense, it's true that Open Source is Viral, not just in the licensing, but in it's development. People who become exposed to it, often embrace it (contract it) to some extent, and it grows on them as they become used to it. They then mention that it works, and introduce others to the concept. Some of these 'infections' produce mutation (new coders adding to the open source, and improving it's fitness)
Microsoft, on the other hand, I think of as a 'Cancerous' development. They take existing methods, and alter them to operate in a way other than they previously did, wreaking havoc in an otherwise established system, often completely breaking it.
There is no 'infection' and rapid mutation to increase fitness of cancer. It just grows, and breaks more that isn't cancerous.

Anyhow, maybe that's a little harsh/dark, but it's how I feel about them these days.

Malk