This doesn't necessarily apply to just blogs, but a user based system would definitely bring some users back to the site. Also, you must provide them with something that they need everyday, which might be news related information, a useful web application, etc.
Their servers had to process five hundred thousand URLs in under 10 minutes on Saturday morning. That is insane! I personally don't use facebook so I didn't get a URL, but it would be a great advertising opportunity for someone who got a dictionary word URL or even a common name.
Posting something extremely controversial will definitely generate comments and new ideas. Posting about something everyone in your audience agrees with will only generate the basic sycophantic comments, whereas a subjective issue will cause some conversation.
The best way to generate traffic to your blog would be to target certain audiences. You should choose a specific subject and target your content towards that audience. You could also use Adsense to buy content on websites and other blogs with similar information and audiences.