Digg can be a good measuring stick on the popularity, or viral nature of content on the Web. If a story is gaining momentum on Digg, you can be sure it's spreading throughout the Web's myriad of channels. Digg stories can also be a good place to find content ideas.
Disstill.com lets you filter Digg to return the hottest stories, either by the hour, by day or by week. You can also set the minimum number of Diggs a story has to return in the results. You can see the results on the website, or subscribe to a RSS feed with your chosen parameters.
Many of the stories may not apply to your industry, but getting an idea of what types of stories are gaining momentum out there could generate some great, related content ideas to take advantage of the surge.