Thanks, J!
Bunsen (Burner?),
The setup here is the same as my previous posts I've had on here regarding the Mac 512K. I'm using software called EasyShare on the Mac 512K, which shares out a floppy drive over AppleShare. I'm connecting with a LocalTalk cable to a PowerBook G3 (WallStreet). From there I'm running some FTP server software called Rumpus. It takes the Mac 512K's share and shares it out over FTP. That gets me to the modern world.
I'm using the Notes application and iCloud syncing to get my message to the iMac. I found where incoming Notes leave little flag or temp files deep inside the user profile on Mac OS X 10.8. I setup a folder action on this folder, so that when a new item appears, it runs an AppleScript.
The AppleScript reads the newest Note and converts it to a text file. The text file is then parsed for information. In my case, if the word was "Listing", it creates a text file of the current items in the folder where I store my Mac 512K apps, then FTP's the text file down through the bridge Mac and onto the Mac 512K.
If the Note contains a number, the script FTP's the application that corresponds alphabetically with the number sent. I used "6" and it sent "Stunt Copter", which was the 6th app down alphabetically.
If the Note said "Night Night", I shut off the iMac.
Once you get this setup, the sky's the limit. It doesn't have to do anything with a Mac 512K. You could control anything you Mac is capable of doing through Siri by using this general setup.
Hope this helps!
Niles