Microsoft stole a lead on Google on Wednesday as its new Bing search engine became the first to let users search the deluge of tweets flowing across Twitter, along with similar status updates on Facebook, in real time.

However, Google moved quickly to counter its arch-rival’s advantage, hurriedly announcing later in the day it had reached an agreement with Twitter for an instant search service of its own. It did not say when the service would be launched, but promised it would be “relatively soon”.