Web: Social networks are a good barometer of what's popular on the web. BuzzSumo is a search engine that crawls through links people share on these social networks and ranks them accordingly.
So if you wanted to find out what people are reading about the Malaysian Airlines Flight 370 right now, you could head to BuzzSumo and search for it. The results will show you links sorted by how many total shares they have got combined on Facebook, Twitter, Google+, Pinterest and LinkedIn.
BuzzSumo lets you filter the list by each social network, by time (past day, week, month, 6 months) and by type of content (article, infographic, video, guest post, giveaway, interview). So you could easily find a giveaway for a new PlayStation 4 with a few clicks.
There are a few search parameters, including the minus sign to exclude words, using OR to search multiple words, or quotes to search an exact term. A super handy feature is that you can save your searches, complete with filters and sort order, making it a powerful reference tool to come back to later.
Apart from content, you can also search these social network links by the people who share them. The Influencers tab lets you filter users by bloggers, influencers, companies, journalists and regular people, and includes another ability to "ignore broadcasters" so you don't get spam in the results.
BuzzSumo is currently free but the company says it will be launching a Pro plan soon, which includes detailed reports, ability to crawl and generate a report for a custom domain in real time. But for regular users, the free account will still get the job done.