Materials ('mats') - items that get used in professions. This is driven more by use than by source; for example, copper is very easy to mine, but it is widely in demand, and you can often find bargains in copper, bargains you can profit from. Contrarily, some very scarce mats may have low demand, may only be used in one mediocre recipe, and may not sell.
Then 8.0 came along and turned everything on its head. Most of the techniques and shortcuts discovered, after 7.3.5 introduced scaling, were nerfed into oblivion. Many of the old techniques were confirmed by myself, first hand, to no longer work. I'm hoping that this thread can serve a similar purpose as the old thread, and gather as much data as possible on the fastest methods under the new system, and facilitate as many different perspectives and opinions on speed leveling with constructive discussion. I've just finished leveling to 110 under 8.1 with the exp curve.