Trending

Dataminr
Tool for catching what's news on Twitter before it trends.

Google Trends
Real time search info. Break it down by day or region. Pulls data from YouTube and Google News as well. Insights on what people want to know right now.

Realtime
What’s trending on the Internet based on bitly, the URL shortening and bookmarking service.

Reddit*
What’s new and what’s popular online. Submit your own links, or vote on others to drive what’s appearing on the front page.

SocMetrics
Allows you to ID influencers; the competitive influence feature allows drill down on brands.