Ubiquity allows you to execute web related actions by writing commands with a natural syntax, in a way somewhat similar to Gnome Do. I’m not going to show any example because I can’t find a good way to explain all of it’s potential, other than “try it yourself” (ah, and pointing to the video here).
You like it? Great; here is some good news for those of you involved with new applications packaging: Thanks to the efforts of Olivier Girardot and Jonathan Winandy there is now a “revu” command which will show you the last comment for any package and open its details page in a new tab if you press [return]. And for those who want to be notified of new comments instead of hunting them down, I remember that there are also personal/package feeds available since a while.