Why is the twitter-yahoo! mashup important?

I'll tell you why.  For the last few years, as the technology of Google, Yahoo and other search engines has improved, their ability to find current or virtually real-time publishing of traditional news has improved.  The obvious problem with this is that real news is restricted to articles or even blog posts that are 'Written'.  These may be copy-edited, spell-checked, proof-read, (or not) but at the end of the day, they are longer than 140 characters.

Microblogging, on the other hand, using services like Twitter, limit entries to 140 characters (inclusive of a URL if you want to add one) but take very little effort.  For this reason, they are incredibly up to date.  As that plane went into the Hudson last week, people were sending tweets before the mainstream media even had boots on the ground.  When Steve Jobs announced after Macworld that he was taking six months off to recover from his health issues, it was on Twitter

in real time

 and traditional media heard a beat before they got the news out.

SO-- to combine the real time 'trend discovery' of twitter with the breadth and depth of a Yahoo! search is a marriage made in heaven. Tweetnews is the bomb. (It's a little overloaded right now though...)  As a marketer, this has also become the absolute best place to monitor media (both social and traditional) for PR hits to your brand.  I forsee this kind of integration happening all over the place as traditional media outlets attempt to add 'Breaking' to their news.