These companies, below, have demos available on their sites.
Product descriptions are in their own words.
Its firewall relay technology lets you use 24Link from behind the strictest of firewalls without breaching any of your network's security. 24Link allows file sharing of any type, size and quantity and provides secure connection with encryption of shared files and authentication of all users. It ensures that files are automatically up to date and document file history is maintained. This can all be done without PC or server administration. With 3Path users can send and organize time-sensitive information in a branded folder directly on their customers' desktops, capture customers' attention with 3Path's delivery notification, tailored to their preferences and ensure that large files are delivered without interrupting customers' online activity.