This is a list of a few fan made websites that can be helpful to new or old players alike.
1. Curse - This is a Website that lets you choose from a wide variety of add-ons to the game. Ranging from rare trackers to UI customization and everything in between. If you are new to add-ons feel free to ask in guild and somebody familiar with them would be glad to walk you through the installation process.
2. Icy Veins - This is a Website that is great for covering talent specs. as well as rotation help and in depth guides/class forums. This will be really helpful in understanding all the changes that occurred with patch 7 (lead up to Legion).
3. Petopia - A great hunter resource on everything related to your hunter pets. Guides on how to find rare pets, what to do to tame certain pets, and in depth discussion on the pet functionality in regards to your hunter play style.
4. Warcraft Pets - If you enjoy the pet battle aspect of the WoW Universe you will love this resource website that specialized in everything Pet Battle related.
5. Ask Mr. Robot - This is basically a gear optimizer website. You simply input (import) your character and it gives you advice as to what gear, enchants, or gems you should go after and or equip. Some players swear by this site and others take this sites recommendations with a grain of salt and experience. It is a good site to play with if you are curious about min/maxing and all its various intricacies.
6. Wowhead - Simply put this is a site that covers ALL of WoW. It is a huge database and lively forums. Anything and everything related to WoW can mostly be found here. Petopia actually utilizes wowhead as links for its map locations and other various information. It is truly the biggest WoW fansite there is available.
These sites are not listed in order of importance. You can utilize the websites or not and its entirely up to you. GSCH has some very knowledgeable WoW veterans so feel free to ask in game with any and all questions, or here in the forums. Enjoy the game and have fun.