Google (Nasdaq: GOOG) is done washing its Windows, according to a Financial Times article. Microsoft (Nasdaq: MSFT) Windows is no longer an acceptable working environment for new Googlers or upgraded workstations, with the company instead favoring Apple (Nasdaq: AAPL) Mac OS X and various flavors of Linux.

This is hardly a shocker, given that Google and Microsoft are head-to-head competitors in an increasing number of areas. Google's infrastructure has a storied past of Linux dominance, and Big G has its own Linux-based operating system working its way toward commercial introduction later this year. The policy change has reportedly been in the works for a long time, but the Chinese hacking scare in January was the final straw, as some Google employees cite "security concerns" as the triggering factor.

That reasoning rings a bit hollow, though. Security holes in old versions of Microsoft's Internet Explorer browser may or may not have contributed to the China incident, but the recent Explorer versions shipping with modern Windows installations were never blamed for that breach. And with that reasoning, Apple computers would be the next to go -- rising market share makes Apple's systems a more attractive target for hackers, crackers, and general miscreants. The same goes for Google's beloved Linux, which is the basis for its own rising Android star and untold masses of consumer electronics. Security by obscurity is becoming an untenable option for these systems.

But taking the average Googler's Macbook Pro away probably involves physical effort and cold, dead fingers. The anti-Microsoft attitude seems more like a directional statement than a security concern. Microsoft really is Google's enemy in more ways than one, while Apple looks more like a co-competitor and occasional partner.

Google and Microsoft may cooperate on cooling standards for data centers, but that's in a consortium with Nokia, Amazon.com, and a number of specialists from that industry. In their incompatible day-to-day quests for world domination, these two are mortal enemies.

The battle lines have been drawn, and the "no Windows" policy is just more chalk on the ground.

Fool contributor Anders Bylund owns shares in Google, but he holds no other position in any of the companies discussed here. Microsoft and Nokia are Motley Fool Inside Value picks. Google is a Motley Fool Rule Breakers choice. Apple and Amazon.com are Motley Fool Stock Advisor selections. Motley Fool Options has recommended a diagonal call position on Microsoft. Try any of our Foolish newsletter services free for 30 days. You can check out Anders' holdings and a concise bio if you like, and The Motley Fool is investors writing for investors.