Launched with little fanfare late last year, Microsoft's adCenter Content Network initially only included Microsoft web properties. Now there are signs they're opening up the network to include high-quality publishers like financial data provider EDGAR Online.
As far as I know, this is the first non-Microsoft web property to carry adCenter ads. Microsoft execs told me early last year that they were planning to build their Content network slowly and selectively, to ensure publishers were high-quality so that advertisers would achieve better ROI than they now do on Google and Yahoo's Content networks.
Though its click inventory is miniscule compared to Google's, adCenter's Search network regularly produces astronomical conversion rates. If Microsoft can deliver the same kind of ROI advantages as it grows its Content network, advertisers hungry for click inventory will flock to it.
Microsoft's entry into the PPC advertising fray has been quiet and cautious - but never underestimate the behemoth's capability to come from far behind and win. Anybody remember former titans Visicorp, Lotus and WordPerfeect?