Sure, FileTrek offers 5GB of online storage for nada, zilch, zippo, aka no cash. That's a great deal in this day and age, when most online storage vendors are backing away from the free model. However, FileTrek is far more. It's a collaborative workflow manager and file revision tracking tool that may just change the way you work, as well as the way businesses manage their data and intellectual property.
FileTrek consists of an online storage repository, local clients to track file usage (this is completely optional), and some very clever software. It's the latter two that make the service so interesting. Any file service could keep track of what's uploaded and downloaded from an account, even a shared one. But the FileTrek local client works in real time at a very granular level, tracking when a document changes, and even when parts of a document are copied to another.
FileTrek also works with multiple users within a workgroup that you define online. First you create a project, then you add users to it. Currently, project users have full access to any documents in the project. Once you've added files, you can either track their usage online or using the local client software. It's quite interesting to see "the fan" as File Trek calls it, or visual display of revisions, users, etc.
All versions of File Trek offer storage and syncing. The free version of File Trek only tracks users, while the $20 per month per user version tracks file revisions, and offers more granular management features. There's also an Enterprise version with more reporting and other features, though you must call for a quote.
At the moment, there's no locking of FileTrek documents. Users are on their own to check when someone else is editing a document and not work on it simultaneously. This freedom will work for some situations, in others it could lead to chaos. But this feature is in the works.
FileTrek is fascinating as a work in progress, though it's already very useful now. All the applications for this level of revision tracking probably haven't even been thought out yet. Get it for the free storage, but definitely kick the tires on the collaboration and other features.