Basically, the title of a bookmark can be dynamically updated from the web, so the title is actually content. Some examples are UPS package tracking data, you can have it show where you package is, right in your toolbar. Another is ebay auction tracking, where it says the current bid and time left.
I made one for Sharathon this week, that shows the current total. If you go to our calculator page, and bookmark it, at the top where it shows the page title, click it, and you’ll see the option for the total.