First, I'm just edgy like that. You know, fighting the system, railing against the establishment by shopping at Hot Topic, and so on. Totally a counter-culture warrior.
The second, more serious reason? I had no idea, no idea, that it is as absurdly useful as it is. Other bloggers have done posts about notifications and such, but that sort of thing does not appeal to me. What appeals to me is basically a single website giving targeted, pin-point data on what is profitable and what is not based on practically real-time price captures of my specific faction's AH. I would not believe this without pictures, so here are a few:
So what you are looking at is the Auchindoun-Alliance page on TUJ. Before you go further, I highly recommend you find your own Realm on TUJ's main page, clicking the correct faction, and then bookmarking the website, preferably in your Firefox Bookmark Toolbar (assuming you use Firefox). Now, what you should look at next is Enhancements and Consumables dynamic "tabs" which break down like follows when you mouse-over:
As you can see, it breaks all of the professions down. When you click on, say, Alchemy, you get a page that theoretically puts all of us gold bloggers out of business.
The screen that appears has a lot more information on it than what I have shown above, but I want to specifically show you the Flask section. Namely... look at it. The Undermine Journal automatically tabulates the current market price of mats AND shows you the current market price of the resulting product, all tailored to your realm's faction AH. Are you still sitting down? Haven't fallen out of your chair? I highlighted the Flask of Steelskin as an example of a market in which I can probably net a profit rather easily by purchasing AH mats and turning around and selling the flasks at a mark-up. We can see that there are only 2 Steelskin flasks up currently, but that actually works in my favor for the most part. Meanwhile, I could probably make more profit selling Draconic Mind mats than the actual flasks at the moment.
Outside of some philosophical posts or patch speculation, what could any gold blogger actually tell you that TUJ could not? That is an open question.
I decided to browse the Leatherworking section, and again, I found elegantly tabulated data clearly demonstrating a market I have been a bit too lazy to dabble in, much to my own economic harm. 150g profit margins on the blue leg armors? Yes, please. The Leatherworking section includes crafted epics and the PvP gear and so on as well, so you can check out the pricing fluctuations and competition before deciding for yourself whether to jump back in X market. As far as the crafted epics go, just keep in mind that since Chaos Orbs are BoP, their price is not included in the material cost column.
Did I mention that all of the items listed through TUJ are Wowhead-enabled, meaning you can mouse-over the items for a description or click on them to go to their specific webpage?
One thing that TUJ cannot do (yet) is the sort of AH meta-game that results in Obsidium Shuffling, or figuring out that disenchanting the epic Engineering helms might net a profit. But that aside, if you were ever stuck wondering what you should potentially be doing to make gold under current market conditions, look no further than The Undermine Journal. It is very nearly the last gold blog post you would ever need.