Transfer software license/registration keys to a new Mac
There are a lot methods used and places where licenses and registration keys are stored:


User specific:

~/
~/Library/Application Support/Application or domain
~/Library/Preferences


This might be plist files, invisible .domain.plist and .random.plist files or files and folders containing files with random names. Also specific 'License'-files exist.
Machine specific:

/Library/Application Support/Application or domain
/Library/Preferences


This might be domain.plist or randomly named files, invisible .domain.plist and .random.plist files or files and folders containing files with random names. Also special 'License'-files exist.
Some licenses are bound to specific properties of the host (e.g. MAC-address) and can't be moved straight to a new Mac (e.g. iPartition)
Disk specific

Some Applications use unused/unvisible parts of partitions to store registrations. Also thumb-drives are used.


Some application even require to deactivate a registration before doing a new or clean install (AFAIR a lot of Adobe apps/suites)