Yahoo is adding two new domains to its Webmail service in order to make millions of new addresses available to current and future account holders.

Yahoo Mail , launched in 1997, has about 260 million users worldwide, so when creating a new account, people have to get very creative to hit upon an available address, often ending up with one that is convoluted and hard to remember.

"We have a lot of e-mail addresses out there, and we want to make available more attractive ones," said John Kremer, Yahoo Mail vice president.

Thus, starting Thursday and for the first time, the service will offer addresses in two other domains besides yahoo.com: ymail.com and rocketmail.com.

If they find an address they like better, users with existing accounts in Yahoo Mail or other Webmail service will be able to migrate their messages and contacts to accounts in the new domains, he said.

Accounts in the two new domains will work in exactly the same way as yahoo.com addresses. Yahoo expects to activate sign-ups globally for the two new domains at around midday Thursday.

As with yahoo.com, people will be able to sign up for addresses with country-specific extensions of the two new domains.

In conjunction with eBay Giving Works and Auction Cause, Yahoo will auction some desirable e-mail addresses it has reserved and donate the proceeds to the following charity organizations: The Breast Cancer Research Foundation, Ocean Conservancy, The Point Foundation, Right to Play and World Wildlife Fund. The auction will begin on Thursday.

Ymail.com is a domain Yahoo has never used, while rocketmail.com belonged to the e-mail provider Yahoo acquired in 1997 and re-launched later as Yahoo Mail.