Google is addressing one of the biggest complaints about its free email service by giving people more control over how their inboxes are organized.

The new option announced Wednesday will allow Gmail users to choose whether they prefer their incoming messages stacked in chronological order, instead of having them threaded together as part of the same electronic conversation.

Gmail has been automatically grouping messages by topic or senders since Google rolled out the service six years ago.

But this so-called "conversation view" confused or frustrated many Gmail users who had grown accustomed to seeing all their newest messages at the top of the inbox followed by the older correspondence. That's how most other e-mail programs work.

The complaints grew loud enough to persuade Google to revise the Gmail settings so users can turn off conversation view and unravel their messages.

"We really hoped everyone would learn to love conversation view, but we came to realize that it's just not right for some people," Google software engineer Doug Chen wrote in a blog post Wednesday.

The aversion to conversation view doesn't seem to be too big a problem, however. Gmail ended July with almost 186 million worldwide users, a 22 per cent increase from the same time a year ago, according to the research firm comScore. Both Microsoft's Windows Live Hotmail (nearly 346 million users) and Yahoo's e-mail (303 million users) are larger, but aren't growing nearly as rapidly as Gmail.