Installed perfectly well to it's default directory (Program Files\Microsoft AntiSpyware).
When launched, it sits in the system tray and appears to be monitoring for "threats", pretty much in the same way an AntiVirus solution would. Realtime monitoring appears to be taken care of by "agents", divided into 3 categories,
Internet Agents,
System Agents, and
Application Agents. These agents appear to be watching the so called "soft points" in the "attack surface" of your computer; things like watching dialup connections (protection against rogue diallers), monitoring changes to the Hosts file, monitoring the Windows Services list and more.
There's also a scanner; much like AV software, it relies on definitions/signature files to identify threats. A default scan on my machine revealed one registry key that had been added by some page or piece of software or other that was classed as spyware; a wizard popped up and walked me through removing it. These definitions/signature files can be set to be retrieved automatically as and when they are available.
Checking the "About" box reveals that the software is set to expire on the 31st July - interesting, as it might indicate a commercial approach. This might alleviate the fears of Norton, McAfee et al somewhat about it mutating into free AV shipped with every copy of Windows, thus shrinking their market (but distributing any software with Windows automatically gets it onto a huge number of desktops...).
Looking at the files in the program directory (GiantAntiSpywareMain.exe), and at the readme, indicates that this is not an inhouse product, though - it seems to be the fruit of Microsoft's purchase of Giant. Indeed, visiting the homepage
http://www.giantcompany.com/default.htm reveals this to be the case!
First impressions are positive; I like the fact that it monitors constantly for threats (I would guess that this is similar to Spybot's approach), seems to be quite lightweight, and has a polished interface.
