CHARLOTTE -- When it comes to following political conventions, Twitter may soon trump television.

TV viewership for last week's Republican National Convention dropped sharply from 2008, suggesting interest in this presidential race falls short of some past contests. But the convention was a hit online and on social networks, the latest evidence of the political conversation's gradual migration from traditional media to the Web.

The Nielsen Co. estimates that about 30.3 million viewers across 11 television networks watched convention coverage Thursday night when Mitt Romney delivered his prime-time speech accepting the GOP presidential nomination. That's a 23 percent plunge from the same night four years ago when nearly 39 million people tuned in to watch then-GOP nominee John McCain address the convention and the nation.

The erosion of TV viewership from 2008 was sharper still on Wednesday night when Romney running mate Paul Ryan drew about 22 million viewers for his acceptance speech. That's a 41 percent drop from 2008 when some 37 million tuned in for vice presidential hopeful Sarah Palin's debut on the national stage.

The Republican convention drew an older audience on TV. Of the 22 million who watched Ann Romney speak on Tuesday night, Nielsen found that nearly 15 million were 55 or older. Only 1.5 million were age 18-34.

The 2008 election was an outlier from an otherwise consistent decline in viewership for political conventions over the past 20 years.

The last year conventions drew ratings similar to 2008 was 1992, when Democrats nominated Bill Clinton and Republicans re-nominated President George H.W. Bush. The highest ratings of the television era came at the 1976 Republican convention, when incumbent President Gerald Ford fought back a serious delegate challenge from Ronald Reagan.

There are many reasons the 2012 conventions may be less must-see TV than in 2008 - an historic election in which Democrat Barack Obama became the first African-American presidential nominee and Palin emerged as a Republican star.

Hurricane Isaac drew at least some attention from last week's GOP gathering in Tampa, Fla., a highly scripted affair which offered little in the way of news or surprises. Little news is expected at this week's Democratic convention in Charlotte, N.C., where Obama will be nominated for a second term.

But even as conventions lose viewers on television, they are thriving online and in social media where many younger voters get their news.

"It's not always easy to sit in front of a TV and watch a convention unfold when you can watch it online, on demand or whenever you care to do so," said Costas Panagopoulos, a Fordham University political science professor who has studied political conventions. "The changing media landscape has given people a chance to gather convention information relevant to them through social networks and other nontraditional sources."

There's no question that television remains the dominant force in political communication. Both campaigns have spent millions to beam picture-perfect TV images from their conventions, not to mention the $240 million the campaigns and outside groups have spent so far on televised ads.

Now, thanks to technology, those images are finding their way onto screens other than just the TV set.

Both parties have offered live streaming feeds of the conventions online, and the RNC's convention YouTube channel received 2.8 million video views. Several TV and print news organizations are also providing streaming video and opportunities for online engagement around the convention through their websites and Facebook pages. Search giant Google also has created dedicated convention pages.

The GOP convention was one of the most talked about news events of the year on Facebook, according to data analysis provided by the company. But even there, the average audience was older - the speeches by Mitt Romney, Ann Romney and actor Clinton Eastwood drew the most buzz among people over 55. Only Ryan's speech drew a younger discussion on Facebook.

Twitter, the social networking hub where information is shared through 140-character microbursts known as tweets, has become an influential media force in the convention after being little more than a blip in 2008. That year, the two conventions together drew just 365,000 tweets. This year's Republican convention alone drew 5 million tweets.

Romney's acceptance speech peaked at 14,300 tweets per minute to make it the most tweeted political event of 2012. The speech eclipsed Obama's State of the Union address in January, which drew about 14,100 tweets a minute.

Adam Sharp, Twitter's director of government and news, said people are flocking to Twitter and other online avenues for the conventions because it allows them to consume news where they are.

"You are no longer tethered to that screen in your living room or anywhere else - you can actively participate in these events while you're in line at the supermarket or waiting for the bus. It's incredibly transforming and freeing," Sharp said.

Obama oddly got the last laugh on Twitter as the Republican convention wound down. On Thursday, after Eastwood conducted his rambling monologue with an empty chair intended to be Obama, the president's campaign tweeted a photo showing the president seated in the Cabinet room with a caption that read, "this seat's taken." It was the most retweeted item of the GOP gathering.