Yahoo has confirmed that it will be gin offering users of its Yahoo Mail service unlimited email storage from May, a move expected in advance of the launch of Apple's iPhone.
Yahoo Mail has around 250 million users worldwide, the company said.
The world's biggest e-mail service is scrapping its free e-mail storage limit of 1GB, responding to explosive growth in attachment sizes as people share ever more photos, music and videos via email.
In January at the MacWorld Expo in San Francisco, Apple chief executive Steve Jobs confirmed that Yahoo would provide IMAP-enabled mailboxes for Apple iPhone users. The iPhone is expected to launch in the US in late June, with a UK launch in October, pending telecoms regulatory approval.
IMAP, otherwise know as Internet Message Access Protocol, is a standard protocol for server-side email, allowing client applications to access and synchronise mail with a server-side repository. The operation is similar to the proprietary mechanisms used by Microsoft's Exchange and IBM's Lotus Notes.
Microsoft has a 2GB free e-mail storage limit for its Hotmail and Windows Live Mail services, while Google's Gmail service averages at 2.8GB per user and growing.
"We are giving them no reason to ever have to delete old emails," Yahoo co-founder David Filo said in a phone interview. "You can keep stuff forever."
Officials said the decision to remove email storage limits reflects the plunging cost of hard disk storage as new personal computers store up to a trillion bytes of data and owners of 80GB iPods can carry 100 hours of video in their pockets.
By contrast, when Yahoo first introduced its webmail service a little under a decade ago, it capped individual storage at 4MB per user. At that time, an "ultra high-density" floppy disk for personal computers then held 1.44MB.
"People should think about e-mail as something where they are archiving their lives," said Filo, who remains active in managing technical operations at the company's headquarters in Sunnyvale, California. Filo carries the honourific, and possibly horrific title of Chief Yahoo.
Starting in May, the changeover to unlimited storage should take a month, said John Kremer, vice president of Yahoo Mail.
"We have been closely monitoring average usage. We are comfortable that our users are far under 1GB, on average," Kremer said. "What we see are an increasing number of rich media files as users send more photos."
Two countries - China and Japan - are excluded. "We will continue working with these markets on their storage plans," Kremer said in a statement. Yahoo is a minority owner with partner Softbank in Yahoo Japan and a part owner with Alibaba of the Yahoo business in China.
Filo said Yahoo is looking at lifting caps on storage for other services such as its Flickr photo-sharing service. "We are looking at those on a case-by-case basis," he said.
It's a far cry from when giving away 2MB of data was considered a big deal, said David Nakayama, Yahoo's group vice president of engineering and developer of the RocketMail webmail service, which Yahoo acquired and relaunched as Yahoo Mail in 1997.
In a posting to Yahoo's corporate blog, he said capacity when Yahoo Mail started was 200GB for the entire combined user base.
"I remember getting in a room to plan our RocketMail launch over a decade ago and worrying that our original plan of a 2MB quota wasn't enough, and that we needed to be radical and double the storage to 4MB per account!" he wrote.
