AP Google was served the biggest antitrust fine in history by the European Commission Tuesday. The $2.7 billion fine was aimed at Google's shopping practices, which the EC deemed unfair to Google's competition. Macquarie Research thinks that while the practice probably is unfair, the fine severely limits Google's ability to refine and improve its core product, which could mean big headwinds for Google in Europe. The recent fine dealt directly with how Google shows shopping results at the top of the search, but the company is also facing antitrust investigations into its Android operating system and AdSense advertising platform.