When Microsoft had invited its advertising customers for its annual gathering in Seattle almost a year ago, Terry Semel, who was then the Yahoo! chief executive, was one of the main attractions. News that Microsoft and Yahoo! held talks about a possible merger was leaked just before the event, and everyone was looking to find out more.

This year the scene is not much different. Hundreds of advertisers have gathered at Microsoft headquarters in Redmond for Advance08. They want to know what the software giant has on offer for them. The revelations, so far, are: new ads on mobiles; more effective integration of Microsoft technologies and salespeople with those of aQuantive that Microsoft took over last year; the promise of campaigns across the PC, TV, Zune, Xbox and mobile phone, etc.

However, Yahoo! is the topic that many in the gathering are most interested in. That is understandable considering the fact that the prospective merger between Microsoft and Yahoo! would transform the online advertising spectrum.