How much storage space do I have in Yahoo! Mail?
Resolution
Users who follow the Yahoo! Terms of Service and our anti-abuse controls can consume an unlimited amount of free email storage. This will apply to both new and existing users.
Our new storage system gives you the option to never delete another email. Unless, of course, you want to. The purpose of unlimited mail isn’t to provide an online storage warehouse. Usage that suggests this approach gets flagged by our anti-abuse measures. In order for our system to work efficiently, our abuse control systems may limit the number of emails you may send or receive when it appears your usage is excessive. These abuse control systems may also impact the rate of growth of your account and you may need to create new folders or move some emails to other folders, if you are experiencing response issues.
Yahoo! employs a variety of anti-abuse methods. If our anti-abuse system detects potential abuse we may take action. These anti-abuse controls enable us to better identify users who are not using the service appropriately under the Terms. Our goal is to ensure that everyone benefits from unlimited storage.