if one commits his or her time to an open source project, he or she may be invest a substantial amount of time without getting paid. As much as altruism is appreciable, I wonder whether it "counts" as an activity which can be shown and is valued in job applications. If the company is worth your time and working power, which it should be in my honest opinion.

So I wonder whether there is something like a common practice in open source projects for this matters. Say, something like

Mr. Martin has been working on our project for five years and has contributed this and that,[...] I we wish him very best for his future.

Mr. ChiefofProject

I think this is a just concern. Do have experiences you can share?