If you have ever needed to send a large file to someone and your email account is too slow you may have gone searching for an alternative to email for big attachments. This is how I came across YouSendIt a long time ago. The service lets you upload a file to their servers and send a link to the person that needs the file so they can download it.
Typically, this involves you heading over to the YouSendIt site to send the files. YouSendIt and Yahoo have teamed up to offer direct access to YouSendIt file uploading from within Yahoo Mail. The integration allows Yahoo mail users to upload files up to 100MB in size.
The YouSendIt app uses the APIs from Yahoo Mail and the Yahoo Applications Platform. It integrates seamlessly with the Yahoo Mail inbox making it easy to upload files without having to go anywhere else. Users can also get tracking and more security using the paid premium version from within their mailbox as well.