Hey Dancer -- the heading above new posts will appear in a different color. There are different backgrounds you can choose for your reading here. I'm on the one with purple "paper" and my new posts appear in lime green. (Go to "My home" to choose a reading "skin.") Also -- when I'm on the main page of the forum, there will be a yellow light bulb next to all topics that have had new posts since I last visited.

Some topics get a ton of replies; some, hardly any. There is no set number.

If I were you -- and this is what I do when I'm missing for a few weeks -- is read the posts from a set date -- I usually don't go back more than a week -- and reply from there. If the topic is more controversial, you might want to read back a little further.

On more mundane topics, I wouldn't worry about repeating, because probably everyone has forgotten the earlier posts by now.