Background: In the application I'm working on we have a feature which basically gives you important updates on whats happening in your business. These updates appear as notifications in the header (think Facebook, StackExchange etc.) When you click the notification you get a dropdown with the 5 latest updates and a View All link which takes you to a page with a complete list of updates where the latest (unread) updates are highlighted.
Question: What is the best way of marking unread updates as read? Currently we mark the updates as read after a page refresh i.e. first time you visit the page with unread messages they are highlighted but next time you come back they are not highlighted any more. This is fine for a small number of updates but imagine a situation where there are 20 of them. I would like to avoid adding a "Mark as read" link on every row if at all possible. Any ideas?