Michael Lou in the New York Times reports:

Online donations are emerging as a cornerstone of the fund-raising efforts of Senator Barack Obama and former Senator John Edwards, who have raised roughly a third of their money through Internet contributions, mostly in small-dollar amounts. Senator Hillary Rodham Clinton has been aggressive online as well. Their efforts have paid off with a rapidly growing army of small donors, many of whom have demonstrated a willingness to give again and again.

Newly released data show that for the first six months of the year, the three leading contenders for the 2008 Democratic presidential nomination, Mr. Obama of Illinois, Mr. Edwards of North Carolina, and Mrs. Clinton of New York, raised more than $28 million online, a figure that does not include second-quarter results from Mrs. Clinton, whose campaign declined to release them. In contrast, the three top Republican candidates, Rudolph W. Giuliani, Senator John McCain and Mitt Romney, raised about $14 million over the Internet.