Ping.it lets you create 'Probes' which lets you define where you want to search for content and how many likes, shares, comments and tweets it must have. One sample probe is “YouTube videos on Reddit with more than 1,000 Likes”.
For users that don't want to create 'Probes' they can then subscribe to them as there are hundreds of very specific probes. Easiest is to check out probes on our home: Ping.it.
The unique benefit for our users is that it enables them to stay on top of emerging viral content. Their own smart and personalized web feed.