I was a bit surprised by two of the replies which seem a bit negative. Surely if you don’t want anyone copying your data it would be better not to share it on the site in the first place?
My initial point was that I wanted to know who might have the same people in their GEDCOMs as I have, so that I can get in touch with them to exchange information, not just to do a mindless download. What might be a minor ancestral line for me, which I haven’t spent much time researching, might be a major line for someone else, on which they have a lot of information, or vice versa.
For example, I’ve had great difficulty establishing the exact connection between a known cousin of my grandfather’s. I then found some of the family I was investigating in someone else’s GEDCOM in WorldConnect, with a few snippets of information that I hadn’t found, suggesting that he might have family papers or further information which might help me. Unfortunately, his email address turned out to be dead, so I’ve been unable to contact him. There might be many more examples like this, but I would need to search individually on several hundred names to check for matches, which is why I would like to see a method on the website for doing it.
The GEDCOM comparison utility mentioned is fine no doubt for matching two GEDCOMs but not all the GEDCOMs in WorldConnect at the same time.