CPAN is full of joke modules and I'm not talking about them, we all know ACME::, those are serious projects centered around fun.
What I'm talking about is research modules, something that you're working on, you've got some part working, you would like some feedback from community, but eventually it is supposed to be merged into some other project or re-written?
The important thing here is - if it's going to be merged, and in the meantime someone started using your module, they'd be left out in the cold. How should one warn people about experimental status of one's code?
UPDATE: rephrase the question as suggested by g0n