I also remember WorldHub flooding the market with diamonds, causing diamond prices to tank. In fact, I bought diamonds solely from TheGurw because his prices were so damn cheap (either 2 or 2.5 cr per diamond, can't remember). Everyone else was selling 5-10 cr per diamond. He was also readily available, and I don't recall his diamond prices changing that much.
I don't recall either of them trading (as in exchanging x item of y for w item of z) extensively. Everything was done "item for credits".
If you call my version of price regulation flooding, then sure, WH did lots of that.
Our prices weren't really low. To get the low prices, you had to buy in bulk, which meant you had to have a lot of credits to begin with. If you bought diamonds individually, the only benefit we offered was offline delivery - which we charged for. You had to give us perms to the plot if we didn't have one nearby your location, where we'd leave the items in a chest.
If you wanted that 2.5cr/diamond, you had to buy at least a full stack at a time - Teircen was one of my main customers, to be honest. He'd regularly buy 2 or 3 stacks in a single go, because he knew he could sell them in a matter of days at twice my rate, or use them in his tools. If you bought from WH in amounts less than a stack, it cost you 5cr/ea minimum, plus delivery if you needed it. We also did a lot of business in bulk cobble, stone, stonebrick, and dirt, which had to be purchased 54 stacks at a time for the discount. When it came down to it, we were like the Costco of T9k - good prices, but you had to buy way more than you likely needed. Otherwise, our prices were identical to Teircen's (literally, I had a running list of what he was offering and at what prices). He had the benefit of a wider selection and more convenient location.
WH never drove down prices. I know for a fact that people were still perfectly willing to pay Teircen at his prices, because he kept buying from me
