People say that there is a lot of garbage and junk on the internet, and it's true; there are entire websites devoted to connecting people with too much of something with those who could use it. Alex Steffen of Worldchanging noted once, "There's no such thing as garbage, only useful stuff in the wrong place."

The most popular virtual dumpster is FreeCycle, a network has developed in communities around the world where you can post what you have, find what you need or list what you are looking for. It is not very sophisticated and can add a lot of email to your inbox, and has none of the security or anonymity of more sophisticated systems, but it's BIG, so you can find the most stuff here and the best luck in unloading.

I have used it for years. It is a bit of work if you have a lot of stuff; you have to name each item separately, negotiate a time for pickup and hope that they show up; most do. Brian wrote a great description of how it works on Planet Green.

Other systems with more sophisticated networks include Virtual Dumpsters, where Collin at TreeHugger notes:

Once you register and get a "vDumpster," upload your unwanted wares into your virtual dumpster; other users can search by location or for the stuff they want, and when a match is made, your old stuff gets a new home. You can also search for things you want, and can extend the searching even further by joining or starting a vDumpster Group.

They've made it easy to keep track of what's available out there, providing RSS alerts of new offerings, and have a Forum for users to chat about their virtual dumpster diving ideas and issues. In addition to virtual diving here in the US, the service is also available in the United Kingdom and Australia, and the worldwide network is working on a few features to make it even easier to use: photo uploads, live chat, GPS location finder and more.

SwapitShop brings virtual money to the dump—it is "an online trading system that lets you trade unwanted stuff for points, which you then put towards other items on the website that strike your fancy."

And of course, lots of people use Craigslist. It's ugly but it works.