What're the differences between classes in guild wars 2?

I'm hyped for guild wars 2 but this 'no tank, DPS or healer' business has me stumped. does this mean that each class does exactly the same thing? What are the differences in the way that classes play?What're the differences between classes in guild wars 2?
Professions have different ways, but accomplish pretty much the same goal. That is to say; you don't need to be Profession X to be able to do job Y. You can be a thief and take on a challenge just as well as you could with an engineer, elementalist or warrior.

However, there is a definite difference in playstyle to accomplish those goals. Each profession (they are not classes by the way) play in a very distinct way. The Warrior will need to get into the thick of things, change it up with weaponsets depending on the situation, possibly with the ability to back away and use ranged weapon when called for, whereas an elementalist need to plan things out, pace him/herself, use spells in teh right order and shift attunement from earth to fire or air to water at the right time. A ranger can use traps and his/her pet, a necromancer weaken foes with curses before moving in for the kill using minions, an engineer use the right combinations of firepower, grenades and gadgets, and so on.

But there is no "you HAVE to have an engineer to finish this task/event/dungeon". They have moved away from that sort of thinking.

If you want to learn more of the professions then you can check out the presentations I made of each on my youtube-channel.What're the differences between classes in guild wars 2?
Each profession in Guild Wars 2 will have its own unique feel, its own unique set of skills and its own playstyle. But within that context, they each will be able to take on whatever role is needed in the situation they are currently in... be it attack in melee range, damage dealer from a distance, or support.

The weapons you choose to wield determine which weapon skills you will have available at any given time, which largely determines the role you take on on the battlefield at that time. And even there, an elementalist wielding a dagger will have a completely different set of skills available on it (and do completely different things with it) than a thief wielding a dagger.

Have a look at the different professions on the official website (see link below), check out the mechanics for each profession and the videos.What're the differences between classes in guild wars 2?
There is no definite "builds" for the characters, or so they say. There will be some sort of healing/buff skills and such, but the game is made without the usual MMORPG mindset. Each class will have 5 varied skills with each type of weapon. Honestly I don't know that much about it either, you'll have more luck on the official site's notes: http://www.guildwars2.com/en/the-game/co鈥?/a>