I read somewhere that 20 blog posts a month is about right, if you pursue blogging as a traffic acquisition strategy. Is there science to it or would you just write as much as you can (And perhaps give it way as guest posts for other blogs?)
IMHO, blogging for driving traffic is really hit-and-miss. One article may become huge and generate tens of thousands of visitors in a short time span while hundreds other barely get any eyeballs on them. If traffic is your primary goal, fewer articles while making sure they are as "link-baity" as possible is optimal. Top ten lists, inflammatory titles and easily digestible content. Also get the link to the article out in as many places as possible to maximize the odds of it going viral.
One trick from some major media sites (such as CNN). They keep changing the title of the same article to make it look like it's a new one a few times a day.<p>You may learn what style of title may give the highest click rate, given the same article.