Viral marketing is a broad term used to describe methods for spreading ideas and messages through the internet at blazing speeds. Methods range from online contest promotions for canned spaghetti to subtle, clever videos on Youtube with website subtitles from the sponsor, to social networking site tools for scouring your email address book looking for candidates to invite into your network.

Depending on how these tools are used, they can be very helpful in bringing people into a focused movement to improve the penetration of a product or service; or they can be a greedy, risky way to get what amounts to a free lottery ticket.

I think the approach of posting entertaining or valuable video on sharing sites like Youtube is the least obtrusive. There was a great Youtube video put out by the producers of the TV show LOST last year. It was called something like “LOST in 8:15″, and summarized all the previous seasons in a choppy way, with a witty, flippant narrative, in 8 minutes and 15 seconds. Coicidentally, the show is based on the story of survivors of Oceanic Flight “815″.

Social networking sites like Linked In provide tools for mining your address book; ostensibly in a safe way that keeps you in control of who gets invites. However, tools aimed at accelerating the growth of an email list are potentially more risky. They can anger your friends and associates by making them feel obligated to perpetuate your quest for elusive rewards. They may even have downloadable programs or videos that can scan your address book, and if their intent is more malicoius, they can pretty much do whatever they want to your computer, network and hard disk. Virus scanners may not detect them, depending on how they are packaged.

So, be careful of how much you trust requests that come from friends and associates, especially if they require you to download or launch anything on your computer. These tools should be restricted in a work environment for network safety and staff productivity reasons. You have to draw the line where productivity tools start to become counterproductive and risky.