I'm an individual and not a part of any nonprofit organization. What, if any, tax implications are there for donationware in the US (as a recipient of funds)? The product would be software and/or screencasts.
If you're not a recognized non-profit organization then your income is taxable as earned income, or hobby income, depending on the circumstances. Some would say it may be classified as a "gift", but I would argue that to be a dangerous proposition, and would advise against it.