The person who happens to submit something first shouldn't thereby get the right to choose the title for everyone else. To throw another idea in to the mix of

The person who happens to submit something first shouldn't thereby get the right to choose the title for everyone else. To throw another idea in to the mix of interesting ones proposed here already: When someone submits the same URL with a different title than a previous submission, allow them to see the set of submitted titles for that submission and upvote the best title. The highest voted title (with some smoothing logic to avoid back-and-forth flips) is the visible one. This way submitters can use better titles than the original, but instead of the first submitter determining the title it is decided by the group of submitters. It would also decrease the work for the moderators.