[h=2]do?na?tion[/h] /doʊˈneɪ ʃən/ Show Spelled [doh-ney-shuh n] noun 1. an act or instance of presenting something as a gift, grant, or contribution.
2. a gift, as to a fund; contribution.
When you give money to an author who posts works on these forums, it almost invariably is in fact a donation and not a purchase. A purchase involves entitlement and support. In general, you shouldn't expect that here. You give money, you have the opportunity to see more 'advanced' work from an author. If they decide to stop playing wow, writing CRs, logging in, living, etc, then there's nothing new for you.
If you want to make a purchase and some entitlement, then contact an author and make a deal with them. Then it won't be a donation at all.