Microsoft-Yahoo advertising deal delayed

Both companies were supposed to sign a final deal for their joint advertising venture on October 27 but sources from the companies said "some details remained to be finalized due to the complex nature of the transaction."

Greg Sterling, whose firm, Sterling Market Research, focuses on search-engine marketing suggested that the delay did not mean the end of the road for both Microsoft and Yahoo. "There are a lot of details to be worked out, there's a lot at stake in getting this done," he explained. "The parties are likely still trying to work out some thorny issues."

There is, however, confusion as to who owns what in the deal. Microsoft's AdCenter platform is expected to deliver the ads but this may not go to well with Yahoo as agencies doing self-service will go directly to Microsoft, even though they may be representing Yahoo clients.

Another problem may be mobile search as cooperation between the companies was left open-ended since July. Yahoo was to have an option but not a requirement to use AdCenter for mobile search, according to Sterling.

Meanwhile, speculation suggests that Microsoft may acquire Ask.com to boost its search share.

Sterling agreed that a deal for Ask might make sense. "Ask would give Microsoft some incremental volume and share -- then it just becomes an Ask-branded version of Bing," Sterling said. "The question is: what's the cost?"