Discussion-list highlights -- what's it mean?

Question on interpreting discussion-list page conventions (or where is it all described?):

On the page where currently active threads are listed, presumably in order of most resent to older, I’m not sure what the system is, as to:

What means the difference between normal and s/w paled-out entries?

Check-box before a thread?

The color-coding of the entries in the “REPLIES” column?

Digits in blue spot-circle after a thread title?

Shaded words in a line below thread titles – e.g. “pali”, “sila”, “arahant”,
or groups of such, as in “dictionary pali cped concise”

“Your topic is similar to…” pops up often when composing a post, most often irrelevantly… What for?

I’m not positive about this one, but I think Normal colored threads are threads you haven’t read yet, paled out threads are threads you have read. (or are considered “following” vs “not-following”)

Means this is a question thread, and if there is a ‘tick’ in the check box it means the topic (OP’s question) has an answer provided in the thread.

In the replies column the numbers are grey, dark red, red or orange . The hotter (more orange) the color, the greater ‘like to post’ ratio there is. For example, an orange thread might have 4 posts with 5-10 likes each, whereas a grey post might have 10 posts, only 4 of which have 1 like each.

Discourse knows what threads you read. If you read a thread, it gets set to “Tracking” for you, and will show you a count of new replies. The blue box is the number of new replies you haven’t read yet in a thread you have read before - “new unread posts”

If the circle is grey, it means there were new replies, but they’re “old’” now.

These are ‘tags’. People add them to posts to help categorize them, but in Discourse they actually do nothing. [quote=“cjmacie, post:1, topic:5678”]
“Your topic is similar to…” pops up often when composing a post, most often irrelevantly… What for?

To stop people from posting the same topic over and over again! Sometimes the suggestion box gets it wrong, but it might help you find a post from 2 years ago that’s exactly your question… no need to post again.