The definitive list of the 51 best free & paid SEO tools (according to me)

My extensive list of the best free and paid SEO tools, as well as some top SEO tools I’d like to try. These SEO tools are truly best-in-class!

Google Penguin Update: Over Optimization, “Negative SEO,” and Achieving SEO Quality

On April 24, 2012, Google launched what is being called their Penguin Update. Per Google, this algorithmic update should impact around 3.1% of search queries and is geared towards punishing pages that have been spamming Google, while promoting “high-quality” sites in their search results.