Microsummaries are an interesting concept. It can tie in with the Places system in Firefox 2.0 although I’m unsure whether this is just a concept or a planned feature.

According to the Mozilla Wiki:

Microsummaries are regularly-updated succinct compilations of the most important information on web pages. They are compact enough to fit in the space available to a bookmark label, provide more useful information about pages than static page titles, are regularly updated as new information becomes available, and are linked to the pages they summarize.

For example, you could bookmark an item on eBay. The browser would find eBay’s microsummary and will append information such as time remaining and highest bid to the bookmark title. The browser can then check back every so often to get updated information.