Ad Age has obtained an internal Google document that highlights some of the biggest AdWords buyers for the month of June 2010, offering insight into how big brands are using Google and how much they are spending. According to the documents, the biggest buyers of AdWords in June included AT&T Mobility, Amazon, eBay and BP. Although most of those companies are frequent big Google spenders, BP was a newcomer to the list, spending $3.59 million on search ads in the wake of the gulf oil spill (compared to just $57,000 in the two months prior).

Top Spenders

The top spender in June, AT&T Mobility, spent $8.08 million on search ads to coincide with the release of the iPhone 4. According to Ad Age, AT&T's the third-largest U.S. advertiser overall, so its Google spending is not a big surprise.

Other companies that made up the top 10 include:

Apollo Group - You know them as The University of Phoenix and they spent $6.67 million in June 2010

Expedia - $5.95 million

Amazon - $5.85 million

eBay - $4.25 million

Hotels.com - $3.30 million

JC Penney - $2.46 million — we'll admit, this one surprises us

Living Social - $2.29 million

ADT Security - $2.19 million

Why Brands Buy Google Ads

The data shows us that for big brands, a heavy investment in Google is usually tied to revenue that comes directly from search traffic (as in the case of Amazon, eBay, Expedia, Hotels.com) or in instances where companies are trying to build awareness (AT&T) or weather a PR crisis (BP).

It's also interesting to note some of the brands that aren't on the list. The documents obtained by Ad Age indicate that companies like GM, Disney and BMW spent less than $500,000 on Google ads in June. Even Apple spent just less than $1 million on Google ads, despite its high-profile launch of the iPhone 4.

However, we also think it is possible that some big brands are spending money on search, but not directly with Google. For instance, although Ad Age cites Walt Disney as one of the companies that spent less than $500,000 on Google ads in June, the movie studio released Toy Story 3 that month, a film supported by a massive ad campaign. The film has gone on to gross more than $1 billion worldwide, making it one of the most successful animated films of all-time. It seems odd that Disney would spend only $500,000 on search terms for its big summer release.

What seems more likely, however, is that Disney purchased advertising through companies like Fandango or MovieTickets.com and those companies have their own arrangements with Google. In other words, when it comes to evaluating search spending, don't count out the potential middle men.

This also makes sense when taking a big-picture approach to Google's own revenue. The top 10 brands only accounted for 5% of U.S. revenues for the month.

Google is a big target for advertisers because of its strength in search and because of its ubiquity across devices. We do wonder if ad buys will shift to other outlets, like say, Facebook, as users spend more and more time on those networks.