It's the computer version of the shell game: Two people work on one document, and suddenly there are eight versions. Which is the most recent? Who has it? When you pick the wrong shell on the street, you lose money. Pick the wrong document and similar pain ensues.

Big companies have "knowledge management" and "workflow schema" to keep their documents straight, but they don't work all that well and cost a fortune.

Enter NextPage and its "silver thread," which tracks documents during transfers between people and through multiple revisions. One click on a document, and you can see how many revisions the document has been through, who has the latest and who made changes to an old version. NextPage runs this as a remote service, so you don't have to buy a server or use a special Web collaboration site.

Six hundred million Microsoft Office users unleash documents on the world, and NextPage wants to track all your Word, PowerPoint and Excel files for you. The company’s spent two years integrating its tracking software into Microsoft Office applications, and its client-centric approach makes a great deal of sense.

You create a document and tell NextPage to tag it with a unique number hidden in the document metadata (the document data Microsoft uses to track details). When you e-mail the document to another NextPage user, you get a notice back they have their own version now. When they change the document, you get a notice they changed it, and the new name if they renamed it. When they send the file on to a third person, you get a notice who got it and whether they revised it. 

NextPage uses its silver thread to graphically display where the document went and when new versions appeared. You don't send the document to NextPage and NextPage never sees your document, it just tracks the unique "document DNA" it assigned when you created the document. When you want to retrieve the document, NextPage tells you who has which version. Those files could be on colleagues’ hard drives, in e-mail folders or on network storage boxes. NextPage gives you the information, but it's up to you to harangue your coworkers to make necessary edits and return it.

That's the clever part: Because NextPage never touches the actual document, there are no potential security breaches, no off-site document storage, and no outsiders ever opening your documents. Traditional workflow systems control all the documents completely, but the first time someone sends a file through e-mail rather than through the closed system all tracking breaks down. NextPage just tracks the document, even when you send it to someone who doesn't have NextPage.