I've never understood why people annotate edit conflicts "(EC)" on the talk page. What is the reader supposed to do about it?
I only do that if my comment would seem somewhat out of place coming after the comment it conflicted with but I don't want to rewrite my comment to take the other comment into account. The most common case is simply when I conflict with someone that's saying pretty much the same thing as me. It would seem odd to just repeat what they've said as if they hadn't said it but I may still want to post my reply, for example, it may contain a bit of extra information, but I don't have the time or inclination to rewrite it to just include the parts that haven't already been said.