Meaning of the envelope icons

[elsielover]

How can I find out what the icons, i.e. envelopes, to the left of the thread titles mean? Thanks.

[c-mama]

An open envelope means that there are new posts since the last time you visited.

A closed envelope means that there are no new posts since you last visited.

A black dot on the envelope means that you posted in that thread.

If you see some lines above the envelope - open or closed - it means it's an active thread - posts and views.

A lock on the envelope means the thread has been closed - members can no longer post in that thread.

[elsielover]

Thank you.