Sharing files among various office locations or between home and office computers sounds easy: you make a copy of a file here, and get it somewhere else. Despite the concept's simplicity, however, complicating factors could confound most business computing users. Given that there are several different technologies, figuring out the right strategy will take some effort.

Last year, peer-to-peer file sharing was all the rage, especially in light of Napster's legal meltdown. But before you can make use of this technology as easily as your teenagers share their latest MP3s with their friends, you need to understand the evolution of file sharing and where p2p (as it is coolly abbreviated) fits in.

The File-Sharing Problem

All of us have worked on files at home and forgotten to bring them into the office, or vice versa. When we remember, we email the file to ourselves or to our workgroup. This is the "brute force" method, and it almost always works, provided you haven't infected your document with any macro viruses, that your pals at your other offices have the same version of software and can open your document, and that you aren't both working on the same document and making your own changes and sending them to each other at the same time.

But email isn't very elegant, and only really works if you are collaborating with a single person. Once you have three or more people sending around documents, it becomes hard to track changes in any meaningful way. It also isn't very secure, although you can encrypt your messages with PGP or something similar, which will require a moderate step up in terms of support and understanding.

The next approach is to use the Internet as a big hard disk in the sky. You sign up for one of the free or nearly free accounts with numerous providers, and then proceed to upload the file to your small corner of cyberspace that you can claim as your own. My favorite of the moment happens to be MyDocsOnline.com, which charges a small monthly fee. But dozens of others are out there, too - just search Yahoo or Google for "file hosting." You can also accomplish almost the same effect if you have your own Web or FTP server, and set up particular directories on these servers for incoming and outgoing documents.

The advantage here is that just about every computer comes with a Web browser or FTP client, so there is no need for additional software. MyDocsOnline.com makes use of the WebDAV (Distributed Authoring and Versioning) protocol that is supported by Microsoft Internet Explorer (since version 5.01), Windows 2000/XP and Office (since the 2000 version). The shared Internet disk drive therefore shows up in your "My Computer" listing as just another Network Place. WebDAV seems to be taking hold, with support from Oracle, Novell, Apple, and Adobe either available or nearly so in their products.

Either the Internet disk or a Web/FTP site is better than using email, but again, what happens when more than two people want to work on something together? The shared Internet disk means you have to give multiple people the same user name and password, which is generally not a good idea.

Businesses have a few alternatives. Some services offer ways for workgroups to collaborate, such as Standard Networks' Silock. And Intuit's Quickbase.com will let you share a database around your workgroup and just use a browser to access files, provided that browser is IE.

P2P Advantages (and Disadvantages)

P2P file sharing avoids these limitations. The idea is to first install software on all computers that need to share files. Those of you who have shared music files with Napster and its offspring already have the mental model: you set up a special directory on your PC that is sharable with your workgroup. Anything you deposit in this directory will be available to the group, provided they have access to your account.

Sometimes, setting this software up can be tricky, which sort of defeats the whole purpose of the p2p movement. There are dozens of p2p file sharing products available, however (and some of these companies may still be in business by the time you read this article). This list offers a wide variety of alternatives.

All p2p file sharing technologies have several things in common. First, they use standard Internet protocols, including Web, file transfer, messaging, and the like. Second, they contain software that turns each computer running them into both a client and a server, so that users can share files readily with others. Third, they have mechanisms to search for other users and files, so that you can create instant communities around this shared knowledge - which can spell trouble for business users who don't want their 2003 strategic planning documents spread around the entire globe.

The advantage of p2p file sharing is that none of these products require skilled IT support to get them working. You don't need to set up a special series of IP addresses, redo your domain name server configuration, monkey around with your firewall rules, execute any Web server hosting co-location agreements, or wait for lengthy approvals up the IT command structure. That is the good news. The bad news is that you have to convince everyone you're working with to actually use the technology. Without everyone running the same software, you are stuck going back to email.

P2P Options

The two basic families in the post-Napster era for music file sharing are Gnutella and FastTrack. These two technologies are similar in that they both allow you to share all sorts of files besides music (and parents should note that many of these files contain objectionable content). LimeWire is a popular Gnutella client, while KaZaa is a popular FastTrack client. Below are screenshots of each.

The LimeWire interface.

The Kazaa interface.

Each has its advantages: LimeWire does a better job with multiple concurrent searches of different files, while KaZaa produces better and faster results. When I checked out the products, LimeWire had more users, but KaZaa had more files available. KaZaa also does a better job reporting on the path to different shared users' files, while LimeWire, which is written in Java, felt a bit sluggish when I clicked on its various controls. And with the recording industry trying their best to eradicate all of these vendors, it is difficult to make much of a prediction for these products.

One company that has stood outside the fray is Groove Networks, founded by Ray Ozzie, one of the inventors of Lotus Notes. Like Napster, Groove broadcasts who you are and what files you have to share with the outside world. You can set up different workspaces for different groups of people, similar to how Notes works, only these workspaces contain common things like Word documents, Web pages, and such. You can start discussion threads, doodle something with your mouse on a sketchpad, or jot down some thoughts in an IM session.

Groove has some impressive features: for example, you don't have to "turn on" secure or encrypted communications within your workgroup. It is always on, and there is nothing extra that you have to do. That is a big plus. You can invite others to participate in your little collective via email, too.

The Groove interface.

Groove was just blessed with a big infusion of support from Microsoft in October, and has gathered an impressive series of accolades in its early history. The nice thing about Groove is that you can cut out all the noise of the music/entertainment p2p file sharing services, and still have something that is relatively easy to set up and operate yet offers solid security for any business user.

Still, the 14 MB download for the Groove Windows client software might be overkill for organizations that just want to share files back and forth. And it does take some getting used to - think of where we all were with Notes a dozen or so years ago. The ideal p2p file sharing product has a small footprint and works reliably with various Windows and non-Windows machines. Sadly, we are still waiting for such a tool. In the meantime, if you want to stick with the tried and true, you might just want to investigate using PGP and email for sending your attachments around the Internet.

David Strom was founding editor-in-chief of Network Computing magazine, and his second book, Home Networking Survival Guide, is now available. He will be presenting a paper evaluating numerous p2p file sharing products at the O'Reilly p2p conference in early November.