This post might have been written and published on April Fool's Day, but the content from Patricio Robles is anything but a joke. In fact, it's serious business kicking the tires and taking a "peek under the hood" at your SEO strategy -- like "due diligence." Robles points to Business.com and Mahalo as two examples of two companies hurt by Google's Farmer update.

Eric Enge believes Google's latest social signal is a way to reshape the engine's ranking algorithms. He explains the importance of the change, and how the evolution will unfold. Links will continues to have an influence on the organic rankings of search engine results. "Citation analysis" will come in many different forms, he writes.

We've heard about real-time bidding on display ads, but what about "relaxed-time bidding"? Rob Beeler calls the real-time version "so 2010," and tells us us what it means to relax-time bid. In an April Fool's Day spoof, Beeler introduces "fast, real-time bidding," "childhood data platforms," and "discrepancy networks." The discrepancy lies in publishers reporting one number, and agencies another.

Rand Fishkin provides advice on using and choosing link metrics for research. He begins by explaining how to analyze high-level search engine page results such as determining how specific results made it into the top 10 spaces of a page. He also explains deep SERP analysis -- and why marketers may want to use this link-building tactic.

John Lee tells us five ways to push through the "proverbial PPC wall" to gain the most benefits from paid search campaigns. These common-sense tactics range from building on existing campaigns and tapping Microsoft adCenter, to integrating social, display and remarketing advertising into the strategy.

Kevin Lee provides retailers advice on how to stay out of bankruptcy by explaining mistakes bankrupt marketers made. Lee refers to the biggest pitfalls as "commodity syndrome," "anyone qualified can run the campaign," and "low fee syndrome." Then he explains how paid search marketing could have helped prevent the disasters.

Paid search may generate sales leads, but a Harvard Business Review audit of 2,241 U.S. companies reveals most leads are short-lived because companies take too long to respond to consumer requests. For example, measuring how long each company took to respond to a Web-generated lead, 24% took more than 24 hours, and 23% of the companies never responded at all.

Does Google save the world $65 billion a year? It does -- according to Google Chief Economist Hal Varian, writes Christopher Mims. Varian calculates it by person per average hourly earning, Web searches, days per year, number of users, and people employed.