According to eMarketer data from January through June, Facebook’s share of US online display ad revenues will grow to 17.7% in 2011, up from a 12.2% share last year. Facebook is expected to see $978 million in additional display revenues in 2011—more than display revenues will grow this year at Yahoo!, AOL, Microsoft and Google combined.

US display advertising revenues at Google will top $1 billion for the first time in 2011, as the company’s share of overall US display revenues grows to 9.3%, eMarketer estimates. That’s up from an 8.6% share in 2010, when Google’s US display revenues grew an estimated 140.5% to $855 million.

See more of eMarketer’s coverage on US display advertising revenues at top ad-selling companies.

In light of Carol Bartz’ exit from Yahoo!, here’s a brief look at ad revenues at the top five ad-selling companies:

Google’s projected $16.53 billion net US ad revenues in 2012 will be about 60% greater than the other four companies combined. Those deep financial reserves, which Google is using to expand its display and mobile ad offerings, suggest how the “Google vs. Facebook” war that’s often hyped in the media is still not much of a contest.

Yahoo! will continue to be a distant second to Google in total net US ad revenues. While eMarketer doesn’t have company forecasts beyond 2012, Facebook will likely pass Yahoo! in the next two or three years.

A complete report, US Online Ad Spending: The Floodgates Are Open, is available for eMarketer Total Access subscribers. Learn more.

eMarketer estimates that Apple will grab 30% share of the US smartphone market this year. Android will fall close behind with 28% share, after exploding from just 6% in 2009.

Note: Smartphones are any voice handset with an advanced operating system (e.g., iPhone, Android, BlackBerry, Windows Mobile, etc.) and features/capabilities that resemble a PC.

A complete report, Smart and Getting Smarter: Key Mobile Device Trends for Marketers, is available exclusively for eMarketer Total Access clients. Learn more.

Facebook’s share of US online display ad revenues will grow to 17.7 percent in 2011, up from a 12.2 percent share last year, according to eMarketer.

US display advertising revenues at Google will top $1 billion for the first time in 2011, as the company’s share of overall US display revenues grows to 9.3 percent.

For more of eMarketer’s insights and analysis on the display ad competition, click here.

Here are a few of the top stories in which eMarketer data and analysis were featured this week:

5/13: The Washington Post – Google under government investigation for online pharmacy ads
Government officials are investigating whether Google profited by displaying ads from illegal online pharmacies, federal regulators said Thursday. Read more.

5/12: paidContent.org – Facebook Marketer Buddy Media Acquires Social Analytics Provider Spinback
With Facebook expected to outpace Yahoo (NSDQ: YHOO) as the biggest outlet for display ad dollars in the U.S. this year, any company that has even an ancillary connection to the number one social network is going to be in play. Read more.

5/12: MediaPost.com – Microsoft Buys Skype, but Ads Have No Role (Yet)
Skype shares many of the basic defining elements of social media: namely, it is an online platform that allows people to communicate in a new way that costs less than previous communication channels. Read more.

5/11: Crain’s New York Business Online – Secrets of 10 top Twitter ads
Advertising on Twitter is a strange hybrid of paid and earned. You can buy keywords on Twitter, but a promoted tweet won’t do much unless it resonates with consumers and they are inspired to pass it around. Read more.

5/10: MSNBC.com – Crowded coupon industry competes for users
Call it group coupon overload. These days it is nearly impossible to browse Facebook, accept an Evite or read a local news website without being tempted to get a massage for 70 percent off, a dozen cupcakes at half price or a skydiving lesson for one-third the usual cost. Read more.

5/9: AdAge.com – #Winning on Twitter: the Top 10 Promoted Tweets
Ads on twitter are a funny hybrid, a combination of paid and earned media. You can buy a bunch of keywords on Twitter, but a promoted tweet won’t do much unless it resonates with consumers and they are inspired to pass it around. Read more.

5/9: AdWeek.com – Even in iPad Deal, Condé Nast Keeps Focus on Print
There’s no question that the news of Condé Nast finally making subscriptions to its magazines available for sale on Apple’s iPad signaled a big digital advance for the company and the publishing industry in general. Read more.

5/9: Wall Street Journal – Digital Ad Firms Crash TV’s Upfront
Digital ad firms and start-ups are crashing one of the television industry’s biggest events—a procession of glitzy presentations to advertisers dubbed the “upfront”—by hosting competing events and parties in a bid to tap into the annual ad-spending frenzy. Read more.

5/8: USAToday.com – Can mobile-phone ads be more like TV? Should they be?
Paran Johar set out last year to make the mobile-phone ad industry a little more like TV by creating the first industry “upfront” conference to put advertisers and programmers in the same room to make deals. Read more.

For more of eMarketer’s recent news coverage, click here.