[foobarkey]

I am currently using identifiers that encode the source and type in them. Mainly did it to make sure various backoffice ID-s never overlap, but added type since it is sometimes useful to identify object type just by looking at ID. This article is a bit discouragong but I have seen this also work well in practice so I guess we shall see how it works out. In any case the problems mentioned are unicorn++ problems and I would be happy if we need to tackle them :)

[srvaroa]

My main advice would be to obfuscate those identifiers in a way that you can use the semantics in the very specific system do want/intend to, but prevent the rest of the organization / systems / external world from using them for their own purposes. At the end of the day it's about not turning them into a public API (which means you lose control over them).

[foobarkey]

Yes I am using 2 digits code for source and 2 digits for type (0-9)