I recently inventoried the list of PowerPC software that I brought over from OS X 10.6.8 to 10.8 to determine how many I needed to delete because they’re no longer supported.
Address Book Exporter 2.1.2
CanoScan Toolbox X 18.104.22.168
Caststream Player v2004
DiskWarrior AppleScripts c.2006
DynDNS Updater 1.2
Starry Night Enthusiast 4.5
Toast Titanium 6
TuneTech for iPod 1.0.1
Who’s There? for Mac OS X 1.3
Windows Media Player 9
Zinio Reader 2.2.6496
The above list is but a tiny sample of all of the PowerPC apps that won’t run on either Lion or Mountain Lion. My 8-year-old CanoScan LIDE 80 scanner is the most critical casualty of the upgrade. Neither Canon nor Hamrick Software (the developer of VueScan) offer software updates that would enable the LIDE 80 to run under Mountain Lion. It appears the only way I can run the scanner on my Mac is via a virtual machine install of Windows.
Mac OS X has supported Telestream’s Flip4Mac media player as a replacement for Windows Media Player for several years. A Mountain Lion-compatible version of the DynDNS Updater is available as a free download from the Dyn.com website.
A software app not on this list that was developed for Intel Macs but is incompatible with OS X 10.8 is VMware Fusion 3. Fusion 5 is required to run guest operating systems on Mountain Lion.