Can I use the Bookmarklet Toolbar on Flash content?

No - the toolbar cannot directly interact with any Flash content. You can still annotate the HTML content on a page that contains Flash, just not the Flash object itself. Some tips to determine if something is Flash content:

• If it is highly animated, dynamic, or interactive. If it doesn't act like the rest of the web page, it might be Flash. For example, Youtube videos are Flash objects.
• Right click on the content. If the menu that shows mentions "Adobe Flash Player" then it is a Flash object.