BubbiBubba, commenters will know you have responded if they have checked "subscribe to the thread" in their User CP. To do this, or to check which threads you are subscribed to, go up to User CP and click on it. On the lefthand side you will see a list of things to do. Under Settings and Options, click on Edit Options. On the next page, under Messaging and Notification, there will be an option to modify your subscription notifications.
You can also manually manage which threads you are subscribed to by going to User CP. In the middle of the page will be a list of the most recent threads you have subscribed to. From there, you can unsubscribe if you want.
I believe everyone's default notification is set to Instant E-Mail notification. This means you'll get a notication that someone has replied to any thread you have started or any thread you have posted in. Also, you will get notifications for tropicalfishkeeping, which is the bettafish.com mother site. Your password and user name are good for logging into that site as well.
As for the fiber thing . . . OFL can correct me if I'm wrong, as she knows much more about this kind of thing than I do, but I believe it's the type of fiber. The fiber that is in pellets is an indigestible kind based mainly on wheat germ. The fiber in daphnia and brine shrimp is a different kind of fiber that bettas can digest.
I, personally, don't soak my pellets beforehand. With 19 bettas to feed, that would take me a while. -__- So far, I haven't experienced any trouble.