You can now add phrases 2-7 words (separated by spaces) in length to your campaigns and ad groups as negative keywords. Added support for negative keywords:

• In the AdGroups service — in the NegativeKeywords ad group parameter.
• In the Campaigns service — in the NegativeKeywords campaign parameter.

You can now target mobile app ads by user interests in API version 5:

• The Dictionaries.get method returns a reference list of mobile app categories to use as interests.
• Methods of the AudienceTargets service now have the InterestId parameter (ID of an app category interest).
• Added the InterestsChanged response parameter to the Changes.checkDictionaries method.