when i am fixing my yahoo! account, i accidentally seen this.
it is very useful.
[quote][b]AddressGuard™[/b]
If you're ever worried about giving out your email address on a web site, AddressGuard is for you. Instead of leaving your address open to spam, you can use a disposable email address, while still accessing all your mail in one place.
You can create up to 500 disposable addresses with Yahoo! Mail. Use these when you want to give an email address to a site that you suspect might share or sell it. Create several if you shop at different places and want to have a different email address for each store, mailing list, etc. You can view messages sent to each of your disposable addresses in your Inbox or a folder that you designate.[/quote]
[i]credits to antispam.yahoo.com[/i]
for more info, proceed to
[url]http://antispam.yahoo.com/tools?tool=3[/url]