LibHunt - LibHunt tracks mentions of software libraries on relevant social networks. Based on that data, you can find the most popular projects and their alternatives.
Q-Stats - Get free marketing insights for every question on Quora.
Ruby Toolbox - Explore and compare open source Ruby libraries
Site Rank Data - View historical rank information of websites via time series charts.
GitNews Web - Trending repositories from GitHub, HackerNews & Reddit
HypeStat - HypeStat is free statistics and analytics service, where you can find information about every website.