The actual developer of this free Mac application is Mike Richardson. Spy X for Mac belongs to Internet & Network Tools.
From the developer:
Spy allows you to run a small server on your Mac, that when accessed by any normal Web browser, allows people to see your screen, as well as information about your Mac.
But it doesn't stop there - they can look at a normal static image, or they can look at your screen, live, in real-time! You can also choose which image format you want to use - JPEG or PNG.
You may want to check out more Mac applications, such as Spy vs Spy, Spy Cam or Plug Spy, which might be related to Spy X.
Network Tools
Antivirus