Barack ObamaBarack Hussein Obama'Too Far Left' hashtag trends on Twitter Krystal Ball: Patrick's 2020 bid is particularly 'troublesome' for Warren Deval Patrick: Biden 'misses the moment' in 2020 campaign MORE is getting more visitors to his website and more mentions on blogs than John McCainJohn Sidney McCainDonald Trump's 2020 election economic gamble 2020 Democrats make play for veterans' votes The Memo: Democrats confront prospect of long primary MORE, according to Nielsen's Internet ratings.

Obama's site received 2.3 million unique visitors while McCain's got 563,000 during May, according to Nielsen. Obama also received about double the amount of mentions on blogs and discussion boards than McCain.

"Barack Obama got a head start during primary season in using the Web effectively to garner support, both in terms of votes and donations,