Many people still think that drugs are legal in the Netherlands. In fact, they're not. Soft drugs are illegal, but tolerated to a point (not more than 5 grams of weed for instance). With that said, keep in mind that police officers are always allowed to order you to give up the drugs, even if it's less than 5 grams.

Drugs policy in the Netherlands is not meant to stop all people from using any drugs at all. The intention of the policy is to protect users from the criminal underground. This is why use of drugs is tolerated and the government focuses on informing people, not on prosecuting users.

Soft drugs may only be sold in assigned coffeeshops which are strictly checked by the authorities to see if they follow the rules. They may never sell more than the already mentioned 5 grams. Soft drugs may only be sold to persons of 18 years and older which has to be proven by showing a valid ID. The drugs have to be for personal use. If caught selling soft drugs to another person, the same strict rules on hard drugs apply (see below). Using drugs in public is also illegal, so smoke your pot in a coffeeshop!

Buying, possessing or selling hard drugs is illegal, but users possessing small amounts are not prosecuted. It is possible to have drugs checked for purity and quality at the GGD (municipal health service) and other organisations for your safety. Usage of drugs like XTC, speed and MDMA is mostly tolerated.

That having been said, when you're in Amsterdam feel free to drop in to any coffeeshop.  Each has its own personality so its easy to find one you enjoy.  For non-drinkers they are a nice alternative with a mellower crowd.  If you are smoking weed you purchased elsewere be sure to purchase a drink from the coffeeshop you are in.  You want them to stay in business, don't you?

 

Wikipedia's take on the Netherlands Drug Policy