An aside: Microsoft's own internal experience with 802.11b obviously affected their thinking in the simple and robust way in which Windows XP seamlessly manages wireless networking. It's as good or better out of the shrinkwrap than Apple's, which Apple managed only after two years of messing around with the software and its integration with location management software. [80211b News]

While it's not an unusual deployment to test out stuff, Microsoft Research's site has some details of their wireless testbed.

On Microsoft Indonesia's Enterprise site, they have an Q&A with Microsoft's CIO about the wireless LAN deployment at Microsoft's Redmond campus. A Q&A with a Cisco VP on Cisco's site mentions a few more details about their wireless LAN from May 2001:

"For example, Microsoft has about 3,000 access points in their Redmond campus and satellite branch offices. Currently, about 7,000 employees are using wireless LAN cards in their laptops, a number that is expected to grow to 20,000 by the end of the year."
7:16:14 PM  

I noted back on October 22 on this site that PayPal used a system where some characters in an image have to be repeated to confirm the signup and possibly seeing Yahoo adopt it to prevent robots trying to spam Yahoo Groups. Not sure when it added, but they already have a similar system in place.

A Yahoo Group called WebWatch noted the system was added at the end of September 2001.
6:25:06 PM