This may sound kind of noobish, and I apologize, but what is the Ore Dictionary for?

It's pretty much there so that mods who have common ores, such as copper or tin, can use each others items. Say I wanted to craft an RE Battery in IC2, but I only had Redpower2 Tin ingots. The ore dictionary allows the RE Battery to be crafted with tin ingots other than those provided with IC2. It's very useful.

Not just for 'ores', it can be used to provide mapping of any identical 'basic' items between any mods should they choose to use it.

What constitutes a "basic" item?

Anything that does not have functionality on its class, like a stick is basic, a wrench that has the interface handling on the blocks would be, a wrench that has interface handling in the wrench class would 'not' be.

so if id add some kind of wood the wooden planks wood be a basic item?

Yes.

for a basic item to work with the ore dictionary it does need to be added in the code by the mod maker, but the point being that it can be used by any other mod that also has an equivelant item in the ore dictionary (a popular example is copper and tin, all forms registered through the ore dictionary are fully interchangeable.

as fare as i have seen, using it as a programmer, the best thing is for basic items, and mined items, used in recipies, to make a crossmod ore base, instead of needing to mine 10 diffrent Coppers, and 10 diffrent Tins.

 

or if for instance

 

if you needed a re-battery for a recipe you wanted to make.. for instance a IC2 batpack.. it required 6 batteries.. but you only had 4 IC2 re-battries, and 2 RP2 batteries.. it could be really nice to be able to use both types, without the recipe complaining

How effective it is depends on how cooperative other modders are.

 

When you register an item with the ore dictionary, lets say... Plastic Ingots, you're telling the Ore Dictionary "Hey, I have some plastic ingots here if anyone wants to use them."

 

Then, if anyone else designs their mod with an Ore Dictionary recipe using "plastic ingots," the ore dictionary goes "Hey, this mod's got some plastic ingots" and makes the recipe using those ingots.

 

The reason why tin, copper, and silver are considered "standards" is because the "Big Mods" like IC2, RP2, and Forestry all use Ore Dictionary Recipes to make any registered tin, copper, or silver interchangeable.

 

So, you can register whatever items you want, but other mods with similar items will have to do their part in order for the things to be interchangeable.