“Subscribe” and “pin to a main” board menu options in Trello

Question

What do these Trello board options mean:

1. Subscribe?
2. Pin to main menu?

I can't see any actions when selecting them.

Answer 1

Subscribe will get you notifications (and emails) on all cards on the board whenever a card has an action on it.

Pin to main menu is a toggle that enables the board to show up in the 'boards' list on the right/top.