logs covering the search engine marketing industry, including our own Online Marketing Blog, started popping up around 2003 and we’ve been covering SEM blogs pretty well with our BIGLIST of SEO Blogs for the past 3 years or so. One of the dimensions worth considering when deciding which blogs to subscribe to is the social proof of how many others have subscribed to a particular blog. There are other factors at play obviously, like topic, writing style, frequency and level of engagement by other readers, but SEM blogs have been around long enough for the good ones to attract a noticeable following.