I have to admit, I am more than a little ambivalent about Ancestry.com public trees.
*Puts on Curmudgeon Hat* They are, I am afraid, possibly the most significant source of the proliferation of lazy research in the genealogy world not to mention all the circular reasoning and just plain wrongness that is spread by the mindless copying that occurs. *Takes off Curmudgeon Hat*
That said, I have found relatives by following those shaky leaves to other people's public trees. This has made me feel a little guilty about not having a public tree of my own. You see to date, the trees I have kept on Ancestry are ones that I call 'Kitchen Sinks,' those working trees where I put all the people that may or may not be related or I've ever come across in my research to see what shakes loose. I do this to make use of the automated searching capabilities programmed into the website. It is not what I would consider as good genealogy. It is a research tool only.
My 'proper' tree, that is, the one that is carefully researched, reasoned and fully sourced is kept on my computer. I will happily share printouts from this tree with lists of sources and discussion/reasoning but, no I will not give you my GEDCOM unless I know you well enough to know that you share my research ethic. I trained as a historian, I have taught history at a university level. I am not going to be responsible for anyone's lazy research.
But by not having a public tree I am not properly 'cousin-baiting.' It's a bit of a dilemma. As a compromise, I have for the moment, uploaded a pedigree file. Just my direct ancestors, no extra relatives, no linked sources, just names and dates.
Is this unfair? Am I taking advantage of people who do post their full trees publicly? Am I being an ungenerous research snob, as someone suggested?