When you're looking at mass intentions and you see the following...

† John Smith

...is this usually referring to someone who has passed on? And what's the significance of the cross in this context?

edit: Also what are the Intentions?

The cross means that the person has died. An intention for a living person or for something else won't have the cross. Usually. (I have heard stories of Masses being offered for the repose of the soul of someone who was alive and well and in the congregation.)

The intention is a thing that the congregation is praying for in a special way at that Mass.