My understanding
As far as I understood artifacts up to now, is that it was used to know if my project refers to an unfinished build task's artifacts.
Problem
I tried reading more (on jenkins site too) but I'm not sure I understand so easily what they do now. I know that when I promote a build, I can fingerprint artifacts. What does it mean then?
You can then use the MD5 checksum to track a particular artifact back to the build it came from.