When you see blue bots with a number or the letter T in them… you got new stuff to read!
When you see the “T Dot” that’s T for topic, as in this is a new topic to you.
Also when you have new topics, you’ll have a New (#) option on your homepage scheme options. Clicking that gives you a topic list of just those new topics.
When you see a “# Dot” that number seems this pre-existing topic has that many new posts inside it for you.