See Part I.
First, make sure you are measuring traffic. You can get free tools from Sitemeter or Google Analytics.
The best source of traffic are the blogrolls of other sites. First, link to other similar sites in your own blogroll. Click those links occasionally (don't spam clicks, but click the link once in a while). That causes your blog to show up in the other person's referral logs, and they'll often check the link out of curiosity. Don't only link to established blogs, link to a few of the newer upcoming blogs that you read. They'll be very grateful for the link, and more likely to link back to you.
The established blogs tend to have larger blogrolls, and are less likely to want to have to fiddle with it. In particular, it's very annoying to link to someone, and then have them stop posting a little while later. I personally don't really like linking to people who haven't been posting for a few months. Again, content is king. The more you post, the more you seem established and worth linking to.
As you write more, the more likely the search engines will start to pick you up. After a while, search engines (specifically Google) becomes a good source of traffic.
Put your blog into your signature on forums. It's an easy way to generate a bit of traffic. I still get hits from years-old posts on the WoW forums. As well, most other blogs have a field for you to enter your website when making a comment. Fill out fields like that. However, don't be obnoxious and constantly reference your blog in comments on other blogs. Just make a worthwhile comment, and if the people are interested, they will check out your blog.
Traffic builds up slowly and steadily, I find. If you write steadily, traffic will build steadily. Oddly enough, a direct link from large sites such as WoWInsider doesn't really help your traffic. WoWInsider shows up as a massive spike, and it's quite thrilling. But almost always, traffic falls from that spike back to the same level as before. The spikes are noticeable, but don't really make a difference in the long run.
So that's my advice for building traffic. Write steadily. Link to other bloggers, both big and small. Put a link to your site in your signatures. Don't worry about traffic. Write steadily for yourself, and people will come.
I don't really know a lot about advertising. The problem with WoW advertising is that the real money comes from gold sellers. If you get Google Adwords or similar, it's a fair bit of work to filter out the gold sellers, and whatever is left doesn't really earn you much money.
I think I had Adwords for 3 months once, and I made a grand total of $5. Given the amount of time I spent blacklisting gold sellers, it really wasn't worth it, and I dropped Adwords.
Honestly, I have no clue how to make money from a WoW blog. My advice would be not to bother. I'm pretty sure a shift at McDonald's would be better value for time.
Comments can be very weird sometimes. You'll craft something that you think is utterly brilliant, and no one will say anything. They won't even tell you that you are wrong. Yet a throwaway post can generate great discussion. It's odd and hard to predict.
I recommend that you never "ask" for comments in your post. Let your post stand on it's own. It's something I've noticed, but it seems like if the post invites comments, fewer people actually comment. It's not 100%, sometimes people do respond to posts, but it's very hit and miss. Plus, I think it looks a bit sad, if you ask what readers think but there are zero comments. Write as if you don't expect comments, and it is more likely you will get some.
The only surefire way of generating comments is to insult PvP from a raiding perspective, or insult raiding from a PvP perspective. That will almost always generate a firestorm.
As to the rules for comments, I try to make it as easy as possible to comment. I don't require people to log in, or type in a captcha. Every barrier you put up makes people less likely to comment. The easier you make it for people to comment, the more likely they will comment.
Of course, you're probably worried about comment spam if you leave comments wide open. For some reason, Blogger doesn't actually get a lot of spam. I'm not really sure why, but it's another advantage to using Blogger. Occasionally, one specific spammer will pop up and start spamming. What I do then is to turn on Comment Moderation until the spammer goes away. Always have Comment Notification up so you get email when people comment. Sometimes you will get spam and normal comments on really old posts. Blogger now allows you to enable Comment Moderation for older posts, and it's been a big help.
I don't really get very much spam, and what I do get I just manually delete. Captchas and other anti-spam mechanics cut down on spam, but they also cut down on normal comments.
The final topic regarding comments is censoring/deleting comments. My advice is to just delete comments that are insulting or pointless. Try to delete such that people see "This post has been deleted by a blog administrator" or similar message. People tend to follow the social norms already established on the blog. If everyone else is insulting or trolling, then they will insult and troll, push the boundaries a little bit more. Step on it early, delete the first offenders aggressively, and it will keep your blog from becoming like the official WoW forums. Of course, it is important to differentiate between honest dissent, and people being stupid. But in general, people who are worth listening to can phrase their disagreement in an appropriate manner.
Freedom of Speech doesn't mean that you have to put up with jackasses on your own site. They can always make their own blog.
That's pretty much all I wanted to write about. My advice boils down to keep things simple. Write steadily, and write for yourself.