I'm all for knowing the number of other people answeing a question, if not neccessarily their names, reps and so on.
There are some questions where there is little leeway as to what the core of the answer has to be, and how to explain it. But it still takes time, the explaining in particular. Having spent that time just to realize someone else posted the same answer seconds before you did, and discipline requires you to delete your answer immediately, can be pretty frustrating. Had I known that three other people hat started answering that question, I'd have more useful things to do with my time, at least until the first answer arrives and I can decide whether I'd have written the same.
I can only speak for myself, but having experienced this a few times, I changed my behaviour:
- I no longer look at the very fresh questions, but preferrably at those from half an hour ago. No more quick answers from me.
- I more often write the core of my answer in a few sentences, submit those, and then continue editing. And get annoyed if others downvote the rudimentary answer I posted as a placeholder.
I believe neither of these behaviours to be in the best interests of the SO community. If it's only me, then so be it. But if others observe similar behaviour in themselves or others, then I think some kind of unobtrusive notification would be valuable.