I've used Facebook for a variety of ways to exactly to this. In fact, I was able to do even more. I've found apartments and roommates this way. Donating or selling old tech is really easy if you you've got a number of contacts in your social networking circle. The easiest way is to simply put it in your status update directly. A simple sentence will do. If you need to do more, then you can always place a ad in the Marketplace section (for Facebook) or similar section in other social networking sites. One of the reasons why this works well is because your Facebook friends might have similar interests, so they'll be interested in getting vintage video game consoles, cameras, etc.
People are always interested in getting second hand tech because it's a lot cheaper than buying new stuff. I always keep an eye open for DSLRs and laptops. A lot of users tend to upgrade their tech frequently, which means that you can probably snag a year old laptop at a significant discount. The same is true for DSLRs.
That being said, leveraging your social network to marshal up some interest in some stuff that you want to sell or get rid off is usually acceptable, except if you do it all of the time. I usually use it when I purge or move and need to get rid of stuff. Believe me, people are also glad to pick up stuff for free. So before you ferry off your stuff to a recycling center or try to find a way to donate them away, make a status update to see who will come by and pick it up for free. If you struck out at this, you can try the Freecyle Network. [images via Face Off Movement, Channels, ]