McCall, who was speaking at the opening session of the Fipp World Magazine Congress in London, said that MediaGuardian.co.uk is one of the specialist areas that GMG should consider charging for.
McCall said: "More people are looking seriously at how they can make money charging for content that costs a lot of money to make. I don't think we will be doing much content online in B2B unless we get money for it.
"It's crazy that we do so much to put content out there but we don't get money for it."
McCall said the traffic Google drives to news websites is "no longer a fair swap because we can't really monetise traffic in the way we were".
GMG has spoken about charging for online content before.
Tim Brooks, managing director of Guardian News & Media, said at the FT's Digital Media Conference in March that a big organisation such as the New York Times would need to be the first to charge for content and then smaller organisation could follow suit.
He said if he could get his "wish this year it would be that New York Times would put up a pay wall, then we could achieve all our objectives".