1. Email is Not Secure
When files are attached to an email that is sent they can be viewed by other parties, including computer hackers. In order for attachments to get securely to us or to any other intended party you must painstakingly install and maintain problematic email certificate licenses.
Our secured portal allows you to safely exchange files with us. Every file is encrypted using the latest 128 to 256 bit encryption algorithms (depending on your browser). All the security measures are automatically handled by the system.
2. Email Imposes File Size Limits
All email servers have a set size limit for attachments that can be transmitted. This size limit is generally between 5MB and 10MB. If someone attempts to send you an email with an attachment that exceeds the 5MB and 10MB limits the email may simply be rejected without notifying either party.
You can exchange extremely large files, even huge 200 megabytes files through the Secured Portal because, unlike email, it was designed from the ground up to securely transfer very large files.
3. Overnight Courier is Expensive ( Priority Mail,DHL,FedEx...)
Using an overnight courier is expensive and still too slow in today's fast paced business environment.It doesn't cost you anything to use the secured portal. And files and documents are transferred in minutes instead of having to wait for the next morning.A great use of this would be to exchange the tax organizer,W-2's and your finalized tax return.
3. FTP is Inflexible and Administration Intensive
While FTP (File Transfer Protocol) servers do not have the same file size limitations and security problems of email, they require a system administrator to set up and maintain each company-to-company relationship and user passwords individually. This results in FTP being a cumbersome and inflexible solution for exchanging files with multiple outside parties.

Also, to understand the technical security features and benefits of a SAS 70 Certification please read this
additional information.