As the presidential campaign heads into high gear, the candidates and their supporters are blanketing the airwaves with a barrage of ads, particularly in states considered battle grounds in November.\n\nBut on the Web, which commands an increasing share of Americans' media consumption, President Obama's team has made a far greater effort to engage directly with voters than his opponent, former Massachusetts Gov. Mitt Romney, according to a new study by the Pew Research Center's Project for Excellence in Journalism.Members of the Obama campaign have been posting nearly four times as much content on the Web as the Romney team, and maintain an active presence on twice as many online platforms, according to the study, which analyzed the candidates' Websites and various social media outlets over two weeks in June.[Related: Mitt Romney Twitter Account Filled with Fake Followers, Analysis Finds]The disparity was most glaring on Twitter. Over the course of Pew's study, the Romney campaign tweeted an average of once per day, compared with the 29 tweets the Obama team posted, representing the combination of Obama's presidential account, @BarackObama, and the official campaign account, @Obama2012.As of Wednesday, a note on the presidential Twitter account explained that it is now being run by the campaign staff, and most of the recent tweets reinforced campaign messages.But for all of the digital output of the campaigns, both tended to remain rooted in the mode of one-way communications. The Pew researchers found very few instances of so-called "citizen content" on either candidate's online platforms, and while Obama engaged outside voices on the blog section of his official Website, Pew noted that campaign workers could control the content that is posted there to ensure a consistent message.The candidates' online output was generally positive, with each touting his own policies and achievements, the analysis found, though it noted a greater rate of negative posts from the Romney camp. Roughly one-third of Romney's posts focused on criticism of Obama, compared to 14 percent of Obama's messages that targeted his opponent.[Related: CIOs Must Embrace Social Networks to Drive Social Business]Amy Mitchell, deputy director of the Project for Excellence in Journalism, said that Romney has been stepping up his social media and other online efforts in recent days, but that Obama retains a sizable advantage."As the conventions drew closer, Romney's campaign took steps to close the technology gap, and may well take more with the addition of [Wisconsin Rep.] Paul Ryan to the ticket," Mitchell said in a statement. "But there is a long way to go before the Romney team matches the level of activity of the Obama campaign."For Pew's most recent analysis, the fourth presidential cycle it has examined digital campaign efforts, the researchers expanded their examination to include Facebook, YouTube and Twitter, as well as official campaign sites and blogs.Both candidates focused their online messages heavily on the economy, with Romney devoting a slightly greater percentage of his posts to that issue than Obama, hitting the president especially hard on jobs.But posts on social issues such as immigration and healthcare appeared to resonate the most with social media users. For both candidates, their posts about such issues were retweeted or shared at several times the frequency as their economic messages.All told, Obama's posts saw twice as many shares, views and comments as content from the Romney camp.Among the other insights the Pew analysts surfaced was the tendency of the Obama campaign to target more precise voting groups in its online efforts than his opponent. They pointed out that Obama's Website invites visitors to join any of 18 specific consultancy groups, organized by category such as African Americans, women and Latinos.The researchers noted that the Romney site has added a bevy of community pages since the time of their study, though visitors can still only join the broader Romney cohort, rather than the demographically segmented memberships that the Obama site offers.Kenneth Corbin is a Washington, D.C.-based writer who covers government and regulatory issues for CIO.com. Follow everything from CIO.com on Twitter @CIOonline, on Facebook, and on Google +.