Internet advertising spending in the United States increased 23.1% in the first half of the year, to $14.9 billion from $12.1 billion for the same period in 2010, according to figures released today by the Interactive Advertising Bureau.

The online advertising trade group also says that online ad spending for the second quarter of 2010 increased 24.1%, to $7.7 billion from $6.2 billion for the same period last year.

The advertising group said that spending on display-related advertising—this includes banner ads, rich media and digital video—increased 25.0% in the first half of 2011, to $5.5 billion from $4.4 billion for the same period last year. By comparison, the growth rate for the first half of 2010 was 16% compared with the same six-month period in 2009. Spending for digital video advertising increased 42.1% in the first half of the year, to $891 million.

Display advertising accounted for 37% of the spending in the first half of the year.

“The remarkably resilient performance of interactive advertising so far in 2011 demonstrates that more marketers are placing big bets on digital to tell their brand stories,” says Randall Rothenberg, the advertising group’s president and CEO. “This welcome news, in light of the weakness in a large part of the rest of the U.S. economy, confirms that the innovations happening in interactive marketing deliver great value to the industry and to the consumer.”