Freegle (formerly Freecycle in the UK - see here) is growing in popularity on a daily basis yet I'm still surprised and how few people use it. It's a fantastic example of how a simple idea implemented correctly can help individuals and the environment in a genuine win-win situation.
Basically Freegle is a free mailing list (or to be more precise, a collection of mailing lists - one for most major towns in the UK) to which people send a message if they have something they need to get rid of. This message arrives in the inbox of all subscribers and if anyone wants the item they simply reply and arrange collection. It's an unwritten rule that the receiver collects making it a very beneficial service for the giver too when they have bulky items that need shifting.
So unwanted items find homes that need them and every item that is 'freegled' is an item that doesn't end up as landfill.
 
Visit http://www.ilovefreegle.org for more information and to sign up to your local group.

Let me share with you one of the saddest sights I ever saw.
A couple of years ago I was in South Africa spending a month on safari learning to be a field guide. It was a fantastic experience but very hard work. We were up at 5.30 am every day for a quick cup of coffee before heading out into the bush to learn the the trade of the guide. Lessons would end at about 6pm giving us time for a shower and some dinner before flaking out in front of the camp fire.
In all this time we had a single day off two weeks in. A group of had hired a car to go and explore some of the local sights - we had heard wonderful things about the local waterfalls and beautiful forest trails where we could see even more wildlife.
Now of course at most of these locations there were groups of tradespeople selling local arts and crafts. The stalls would be lined up at the side of the road or the end of the car park and they would be flogging everything from oranges to Springbok-skin hats.
The most beautiful spot we saw that day was a huge lush valley with a massive waterfall at the opposite side - it wasn't on our map as a particular tourist spot but as we came out of a road tunnel the land opened up to the side of us revealing this breathtaking landscape and we had to stop for a look and a couple of photographs. The locals had realised that many tourists would be doing a similar thing and had set up camp on the edge of the drop into the valley.
Just as we were taking our snaps and perusing the craftwork on offer one of the tradesmen stood up, grabbed the plastic bottle from which he'd been drinking and hurled it over the edge into the valley. I was quite shocked by this particularly since it was a local (who clearly used this valley as his main income) doing this horrible act of littering. I then walked over to the edge of the valley and looked down to see a whole stream of litter descending from the edge down and out of sight under the vegetation at the bottom of the valley. There were literally hundreds of plastic bottles and bags (which will not degrade for at least 500 years) scattered all the way down and I was close to tears thinking about how much this was hurting all the wildlife which, before these people arrived, were living in paradise.
I saw similar things in Morocco - mostly plastic bags that you would see in their thousands lining the roads, caught in bushes etc. but, although terrible, this seemed more a case of negligence than the active destruction I saw in South Africa.
 
As I understand it there are three main reasons behind this sort of pollution in less developed countries:
Education - many simply do not realise the damage they are doing
Lack of waste disposal services, particularly in more rural areas
Plastics are a relatively new product in many places and people are used to their waste being bio-degradable so still treat it all the same.
 
Damn it makes me sad