I tithe. I don't mean that in a religious sense at all, but it's the way I pay my community back for that support. It's also not just in terms of money -- I count time volunteering and mentoring as part of tithing. It's also not repaying the people who helped me directly, but I don't think that's the important part. The way you pay them back is to "pay it forward" and do for others as those people have done for you.
Seems like an appropriate usage of the word to me. How seriously do you take the 1/10th part?
10% is the standard I follow. It's built into my budgeting at that level. There's nothing magical about the 10%, though, it's just what works for me and is easy to compute. But I also follow the "pay yourself first" rule -- I take 10% off the top of every dollar that I receive, and put that aside for future me. Then I set aside 10% of the remainder to pay back my community. So, it's really 9%.
If it's not religious I don't know why you'd call it tithing, that's not what that word means. For example, I do communion, but not in the religious sense, I take shots and order a frozen pizza at the bar.