I started my tree twelve years ago, using research given to me by my Mom. Her nephew had spent decades working on it, before the Internet existed and when he died it was given to her. I had zero interest in genealogy at the time and put all of his work on a shelf where it sat for several years. Then I picked it up one day and started going through it in curiosity and that's when the bug bit me. I was hooked. I signed up for Ancestry.com in 2000 and started my tree. I gave credit to my cousin in many places where I manually typed in everything, and over the years have added over a thousand individuals to the tree.
I have NO problem with people "using" my tree. Not my cousin's work, not mine. Because my cousin's work, given to me at a time when I was completely disinterested in genealogy, was the actual spark that lit the fire in me. For which I am so very grateful. In the end, to ME anyway, the gift of genealogy lies in the KNOWING where you came from, the history, the pictures, the stories. For myself, I need no credit. Ten years and a thousand individuals later, I am still more than happy to share anything and everything with anyone who wants the information. And I don't feel I need any "credit". If they want to give it, fine, I would appreciate it, but I don't "need" it. I have been frustrated so many times over the years by cynical, greedy and secretive genealogy buffs that I have no intention of behaving in the same fashion. I think a GOOD genealogist has a generous heart and is willing to help others find their past. JMHO, YMMV.