The venture was established in 1997, with a combined investment of $50 million, which brought together all the online assets of Microsoft and all the media assets of PBL, which include the Nine Network, Australian Consolidated Press (ACP) and other PBL assets.
As of April 2006, ninemsn acquired Australian content syndication and mobile publishing leader HWW Limited, who currently syndicate television, movie, music, restaurant and gig guide listings.
Also in 2006, ninemsn purchased 5th Finger Pty Ltd, a leading Australian SMS and mobile marketing service provider. 5th Finger provides a range of mobile solutions for the PBLMedia companies and to many Australian and foreign content providers.
In mid-2011, Ninemsn underwent a major upgrade, which ninemsn stated enhanced the website by making it look better and less crowded. Users can now also set up the website the way they like it, such as saving their favourite web page on the website itself.
Microsoft sold its 50% stake of Mi9 (formally ninemsn) to Nine Entertainment Company in 2013. As part of the arrangement, Microsoft has signed a long term strategic partnership agreement, whereby Mi9 will continue to represent Microsoft’s suite of advertising products.