Bing has just announced a beta Bing search of the public Twitter stream. So far it looks pretty sweet. Two things in particular that I've noticed that make it nicer than the default Twitter search:
1.) When you search for an item, twitter shows you the results. But, when more tweets are posted that should show up in the results, you are only shown a notification "23 more items have been posted". However, with Bing's search, the items are update ajax-style "real-time".
2.) For a few of the major url shortening services, Bing actually displays the domain name of the destination url. I've noticed this for the default shortener bit.ly and tl.gd (Twit Longer). Doesn't appear to do this for tinyurl or the now defunct tr.im.
My big interest in this search engine is in the hopes that they will allow API calls that aren't limited like Twitter's rate-limited API.
If you use Twitter and ever find yourself searching for something, I definitely recommend giving Bing a try. http://qr4.us/bingtwit
To read more about the Twitter Search beta release visit http://qr4.us/bingtwitinfo
It appears that Microsoft will not be satisfied simply with Twitter's status updates, apparently they are leveraging their $240 million investment in Facebook to get the upper hand on showing status updates in Bing. Read more at http://qr4.us/bingfb