A couple things I would add about Auctioneer is that it is a memory hog. If your computer is lagging already in the big towns like Orgrimmar I would either a) not install it or b) use it in a less populated auction house accessible city like Thunder Bluff/Darnassus. The mod stores useful data, and after a while the database gets fairly large causing it will slow your computer down eventually.
The second thing about the article is its download link. Like all programs to download from the internet, I would advise anyone to download the program from the original download site at AuctioneerAddOn.com. I don't have anything against the link that was posted, but sometimes people add in their own malicious code when you download something from a 3rd party site. It also has a nice little donation page too if you are feeling generous, and like the work they do. Feel free to ask me if you have any questions about this mod, I feel that I'm pretty confident about its use.