Tags are a popular way to cross search content.

Display Tags for the current page - this shows tags in your page, and you can add tags in the text box, or deleted with the little X. They are all stored in a custom attribute called "tags", so don't delete that attribute! The tag block we added above would look like this:

Display available tags- allows you to enter how many tags you would like to display. 

Advanced, Tags Link to Location - you need to make a search results page somewhere with a search block on it. Point to that page from here and clicking a tag will take you to the search results page showing other pages that have the same tag you clicked on.