At its simplest (and free) level, it can send you a daily email digest with the most popular links shared by your Twitter followers.
It comes with many other features too if you login to the website or pay up for a Premium account. But the free daily email digest means you can keep on top of the most popular links going around without having to spend the time looking at Twitter itself. (That also gives a spur to pay a bit more attention to who you are following in order to improve the digests. That’s no bad side-effect either.)