It provides a pretty good overview of what's going on on Twitter with customizable columns for any type of feed (filter hashtags, users, keywords, ...). Easily schedule tweets and stay on top of your notifications.
I treasure up tabs constantly during research and then I get lost with lots of open tabs. OneTab helps me reduce the number of tabs, by simply grouping them together and putting them out of sight. But they are all ready to be opened again with just one click.