And to add to Franks note, please don't do reply-all, just reply to the list. When you reply-all the direct reply will almost always get to the sender before the list bounce, so it is likely this is the one that will get the next reply, and that means to you directly, taking the conversation off list.
Also please don't edit subject lines unless you mean to split the thread, the big ugly Gorilla of webmail clients, Gmail, will only thread based on subject. So editing the subject means you split the thread for those users.
Cheers
Lex