I don't. I would if I were at least paid to, but I focus on writing software for myself to generate income instead of generating some multiple of my salary for an employer.

There was an article on HN about an open source developer who is the sole maintainer of some complex, common tool (I can't recall what) who barely scrapes along. He's created many millions of dollars in value for others yet he can barely keep food on the table.

IMO, open source is great for consumers and middle-men, but takes advantage of and devalues software creators.