The Google take-over of Admeld (worth about 400 million) is being reviewed by the Dept. of Justice for anti-trust concerns.

Admeld is a technology and service company that helps large publishers optimize and manage their digital ad inventory–helping them maximize yield.

Google’s interest in Admeld will be to strengthen it’s own ad sales by providing it’s services/products to large ad publishers. Admeld’s clients include Weather Channel, IDG TechNetwork, and large newspaper companies like The New York Times Company, Hearst, Tribune and Gannett. The Admeld network spans both the U.S. and Europe.

This year display advertising has helped spur grow in online advertising. EMarketer places ad spending this year at $31.3 billion, which represents a 20% growth. A new forecast shows online ad spending reaching $50 billion in 2015. Brand-centric ad formats like banner ads, sponsorships, and video ads are actually growing faster than search marketing ads.

Here’s how that $31.3 billion online ad spend is estimated to break down in 2011:

• Search: $14.4 billion
• Banner ads: $7.6 billion
• Classifieds: $3 billion
• Video ads: $2.2 billion
• Rich media: $1.7 billion
• Lead gen: $1.4 billion
• Sponsorships: $900 million
• Email: $160 million

The United States Department of Justice has been investigating whether Google has been displaying ads of illegal or unlicensed online pharmacies. According to a Securities and Exchange Commission filing, Google has set aside $500 million to settle with the Federal investigators most likely over this case.

Included in the investigation were the United States attorney’s office in Rhode Island, the Food and Drug Administration, and the Justice Department.

Google says that it has been trying to clean up it’s advertising program by removing these illegal pharmacies, but the violators seem to be increasing in number and difficult to locate and remove.

The Wall Street Journal recently criticized the Adwords program because of a feature called session-based web ads, which, the newspaper writes, may cause some wev advertisers to overpay. WSJ says that the problem is that the ads are running within unrelated search results–meaning that the searchers within these topics are less likely to pay for the products and services advertised in the PPC ad. The article also points out that some advertisers have limited the scopes of their campaigns to prevent session-based clicks.

This negative publicity comes at a time when Google is struggling to reach small businesses and bring them into the PPC advertising program.