Yesterday, Microsoft started selling hats, mugs, T-shirts, and hoodies with a distinct anti-Google message, bearing phrases like "keep calm while we steal your data" alongside the Chrome browser logo. They're the latest wave of Microsoft's long-running Scroogled campaign, designed to frighten people away from using Google services.

How does Google feel about Microsoft's clothing line? The company appears to be taking it in stride. "Microsoft's latest venture comes as no surprise; competition in the wearables space really is heating up," a spokesperson told The Verge.

"Competition in the wearables space really is heating up."

It's a clever jibe. While Microsoft is only selling T-shirts, Google is hard at work on its Google Glass wearable computing device. Still, Glass is very much a work in progress, and the retort can only reach so far. While only those who pay close attention to technology are likely to read Google's wit, Microsoft's clothing has the potential to reach anyone who sees the merchandise.