As Google moves forward with their acquisition of DoubleClick, they have faced a few setbacks as various regulatory agencies have been probing the deal. Most recently, the EU has decided to further extend their investigation into the deal to see if it would potentially stifle competition. While Google was hoping to close the deal before the end of the year, the EU now says they will not come to a decision until April of 2008.
Obviously this has upset Google, and it may upset them further if the EU decides that the acquisition requires modification to be approved. It has already received the go-ahead in the U.S., so Google still has options there.
Microsoft is still vehemently opposed to the deal, despite them also taking similar measures with their purchase of aQuantive.