Why? Because we're giving away three custom-designed t-shirts in total -- one to a random Ally, one to a random Hordie, and a third to a random commenter of the faction with the most supporters. If more Alliance comment, they'll get the third t-shirt, or if more people shout that they're "For the Horde," then an Orc, Troll, Forsaken, Tauren, or Blood Elf will get the extra freebie. We haven't tallied all of the comments yet, but I believe (this is an unofficial estimate) that the Horde currently have a slight advantage. So if you're Alliance, or you have some Alliance guildies who haven't commented yet, tell them to "grab your sword and fight the Horde!" and send them over to the post. Or if you're Horde, you might want to try and solidify your lead.
The contest ends tomorrow night, Friday the 3rd, at midnight, so while you can only comment once (remember, on that post, not this one), you've only got a day left if you want to get your comment in. Good luck!