Fielding questions in a live web chat last week, Emily Bell said the site was not trying to creep towards a 'pay-per-view' format.
"Our new charges are deliberately kept at a level where the vast majority of the site will remain free to everyone.
"The benefits of having a free website are huge - we are still seeing web traffic expand pretty quickly and on a global scale. I really like the idea that people around the world and the UK who may not have ever heard of the paper before are engaging with Guardian journalism."
Paid subscriptions were introduced on 30 July for the crosswords and email news digest services The Wrap and The Informer. Subscribers can also sign up for an advert-free version of the site. Services cost between £12.50 and £25.00 per year.
Ms Bell also said that translating the site into another language - possibly Spanish or Chinese - would be very expensive but an interesting proposition in a few years' time.
The site may also develop an archive of topics from the message boards - and did consider publishing some of the September 11th threads - but there are no plans to start charging for the extensive Guardian Unlimited archive.
The new Guardian Digital edition, a full online version of the print edition, will soon be available in Portable Document Format (PDF).
One reader asked why the site was beginning to charge long-standing and loyal readers, given that the Guardian Media Group recently tripled its profits.
"We need other revenue streams to help us invest in the site - even trusts need an income of some sort," replied Ms Bell.
"Secondly, you don't have to pay for anything if you don't want to. We run a site which costs the company more than it makes because we believe in online journalism."
Rafat Ali, the technical consultant behind the paidcontent.org weblog, felt the web chat was a brave move by the news site and sets a good precedence for other publishers.
"If one thing is coming out of blogging, it is the idea of 'open source' journalism. Publishers are now more responsive to readers and it's a very effective way of getting readers' input and comments," he said.
"The whole concept of interacting with readers is much more acceptable since blogging."
But writing in the Poynter Institute's E-Media Tidbits on 30 July, Norbert Specker, director of Swiss firm Interactive Publishing, felt that Guardian had handled the transition badly.
He described an email he received without warning, notifying him that his free subscription was now cancelled. "Short, technical and awfully snobbish," he complained.
"Do we need to issue a reminder that there are trusted and proven marketing tactics (such as wooing and courting the existing customer base) to encourage users to upgrade? Too bad you only get one shot at doing it right the first time."
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