Last year the benchmark rated 110 charity websites on the basis of communication, usability, accessibility, transparency, responsiveness and integration.
This year it will include extra criteria for measuring each charity's work in relation to social and environmental responsibility standards.
"We are looking for charities that think they have good, accessible websites and want verification," said Michaela Carmichael, marketing consultant at iConcertina. "There must be charities out there that want to know how they fare against other organisations in the sector."
The closing date for applications is 12 February. The 2007 report will be published in April.