Every Tuesday in WoW is known as "Patch Tuesday." Blizzard has the option of shutting down the servers - all of them in a region such as the US or Europe - between 12:00 am and 5 am (PST in the US) every Tuesday for maintenance and upgrades. They don't always observe the downtime, and it is often shorter than the advertized time. (However, for major new releases such as a new expansion, the downtime can be extended to 24 hours and has become about 72 at least once in the past.) A fact mentioned in the talk given by Blizzard executives at the Austin Game Developers Conference (AGDC), most of WoW's 180,000 documented bugs have been fixed. Rolling out those fixes generally requires the servers to be shutdown, the fixes installed and the servers restarted. The fixes may require the software on your computer to be updated as well. Sometimes those downloads are small; sometimes they are hundreds of megabytes. In the same talk, Blizzard mentioned that at that time, 4.7 Petabytes of data had been downloaded. If you happen to live where there is measured Internet or a cap on the amount of data you can download, this can be a real issue. This isn't an issue for most of the US Internet users. (Click on the thumbnail below to get a sample of some recent bug fixes.)
Bugs aren't the only things changed. Occasionally, Blizzard does "fix" classes to bring them up (or down) to par with each other. This has the effect of making some classes less effective than they were and others more effective. The reduction of class' abilities is called "nerfing" after the popular Nerf brand of foam toys (that hurt less than the real thing). An increase in abilities is called "buffing." Most of this balance is to make all members of a group in a battlegrounds or a raid instance have a reasonable effect on a group. It's a very delicate balance with a lot of interweaving of abilities to make an effective group. The good news is that if your child picks a class that they don't think is performing as well as other classes with similar duties/roles, they might get a "buff." The bad news is that they are just as likely to get a "nerf." Even more likely is that occasionally Blizzard changes the game mechanics in such a way that certain attributes that used to be important to a particular class for a particular role may be combined or switched to another attribute. A lot of the research I mentioned above has to do with maximizing the proper attributes for a given class. Sometimes it takes considerable effort to do so. It can be disheartening for a seemingly arbitrary change to make that work a waste of time. When and if this happens to you or your child, it can be a good lesson about life, but a player has an option of putting up with the change, switching to a new specialty with that character or switching to an entirely new character.
The higher-level instances can really only be defeated with a team of 10 or 25 players (depending on the instance) that are playing in concert. Because of real life schedules and commitments, a guild can't have just 25 members for 25-person raids. Having 25 individuals with the right mix of abilities on hand at every raid time translates into a need for something on the order of 40-50 members or more. Any time that many personalities are brought together, there's going to be some clashes. This is commonly referred to as "guild drama" and those that cause repeatedly cause such strife are called "drama queens." Generally, it's not too serious, but I've witnessed the breakup of several guilds as a result of drama.
WoW is a game at its core, but its players take it very seriously. Almost all guild drama starts with someone feeling they have been unfairly "robbed" of some item that comes from defeating some character in some instance. (Getting an item from a defeated character is known as "looting a drop from a mob" where a "mob" is any mobile character controlled by the computer.) These are usually items dropped by one of the instance's "bosses." We've vaguely referred to bosses before, but the definition of a boss is a uniquely-named character that appears only one place in the game and requires a combined effort to kill.) Before you join or your child joins any guild, find out how the guild does "loot distribution" and raid (instance) invitations. There are many ways of distributing the spoils of war, but any guild worth their weight will have a very well documented and implemented method of doing so. One term you will hear is DKP, which is short for "Dragon Kill Points." Most loot reward systems involve some method of earning DKP for raiding with the group and some way to spend it on items that come from defeating enemies. I've seen some mechanisms that are fairly simple and other that rival rocket science. The most important thing is that the reward system be established and rigorously followed. (Click on the thumbnail below to see an example roster with DKP as taken from the demo at FreeDKP.)
Make sure that you and your child understands that they won't likely get something new every raid, but if they are persistent, they will be rewarded with that "drop" they want. Most guilds repeat the same instances for several weeks or months until it becomes too easy and few rewards are obtained from it (that any of the guild members still need or want). The thing that makes loot distribution especially annoying is that the same loot will drop of the same boss during different attempts. Some of the drops are quite rare. It can be quite perturbing to save up your points for that one fantastic item that never drops, to finally give up and spend some of it on something else and then have the item drop the next week when you no longer have enough points to get it. Blizzard has mitigated this problem somewhat in the more recent instances by having the bosses drop tokens rather than actual loot. The tokens can be used by multiple classes (usually 3 classes for each token type) to be redeemed from a special character in a city for an item appropriate to that class and specialty. Not all bosses work this way, and the tokens are generally for armor items not weapons. Still, this has helped tremendously with the "my-stuff-never-drops" problem.
The other source of guild drama occurs because there may be times when there are 40 people vying for 25 "slots" in a raid group. By necessity, some are going to be left out. The guild should establish exactly how they fill their slots and what is done in terms of DKP for those that are ready to go, but not needed for a given run. Many guilds issue "standby" DKP for those players. They may be called into the raid later if another player needs to leave or has computer or Internet connection problems. Most guilds will also have some sort of signup sheet and fill slots in a first-come, first-taken basis. WoW added an in-game guild calendar just for such things. If people know they will only be available on certain days/nights, they can be given preference on those days, but picked last on the others if they happen to be there.
Unfortunately, a first-come, first-served policy can't always be strictly adhered to. For a raid to be successful, it needs the proper mixture of healers, physical attackers (some of which go toe-to-toe with bosses/MOBs and keep them occupied) and ranged attackers (using magic, guns or bows). Some bosses are immune to certain kinds of magic or deal special kinds of damage, which may require a particular combination of classes. In these cases, it may be necessary to take a person who "just logged on" over someone that's been waiting an hour to join the raid. If this happens occasionally, it's a good time to sit outside and earn that standby DKP while mining ore, gathering herbs or whatever else your character needs to do in their off time. If it happens excessively, it may be time to seek out another guild that needs a player of your or your child's class or class specialty. It may even be time to consider another specialty or another class altogether. These types of problems tend to be cyclic. Whatever class/specialty there is a glut of one month could well be in short supply next month. It may be time to "park" that character for a while and try another.