Digg has ended its exclusive online advertising partnership with Microsoft more than a year before the deal was set to expire, according to ClickZ. The software giant will continue to handle remnant and so-called “network reserve” inventory but, starting in July, Digg will be selling its inventory through its own ad sales force team.

The revised contract is a blow to Microsoft, which in 2007 managed to replace Google as the exclusive online advertising partner for Digg due to the higher level of customization its platform offered. For that same reason, however, the community-driven news site has decided to cut short their three year contract with Microsoft and focus on offering their own custom campaigns for advertisers combined with standardized banner ads.

The decision doesn't come as a complete surprise, though. Digg began hiring an internal sales team in January 2009, leading many to speculate that it could dissolve its exclusive partnership with Microsoft early. Facebook also has a display ad contract with Microsoft, but has been putting more emphasis on the experimental "Engagement Ads" product, which goes beyond just displaying ads and is more closely tied to the whole social networking concept.