White paper: SharePoint Products and Technologies customization policy

I have had several requests lately for a list of supported customizations in SharePoint. Take a look at this extensive document, published in June 2007:

 https://technet2.microsoft.com/Office/en-us/library/95111d67-6ad7-4493-a4e0-f11bd5e787761033.mspx?mfr=true