Marketers have an advantage in knowing the SEO algorithm consists of lines of code written by humans and runs on servers. Yet algorithms change constantly, as often as 400 times per year. This means observations, data, and controlled experiments could become irrelevant. SEO practices built five or 10 years ago are not always valid today. Peter Meyers runs through "fundamental assumptions" and the evidence to support each to prove his point that what worked yesterday will likely not work today.

Liana Evans makes an interesting comparison between Prince's (the artist formally known as a symbol) distaste for the Internet, and ignorance about search engine and social marketing. She explains the problem of allowing fans to have more of an influence on others than those who produce and distribute the music. She walks through the benefits of joining the conversation, or at least being knowledgeable enough to understand the power of search, social and the Internet.

Marketers looking for tips on successful advertising on Facebook might want to turn toward some advice from Dennis Yu. For starters, he runs down a list of major factors that could hurt success -- such as trying to reuse a Google paid click ad on Facebook, casting a broad net rather than targeting, sending traffic to your Web site instead of your Facebook page, and more.

Laura Lippay wraps up a series on an eight-step strategy for search engine optimization with tips on prioritizing and summarizing campaign plans. For example, she tells us why it's important to not only summarize the goals to the client, but explain the potential outcome and the original set of recommendations.

Stephanie Bodoni tells us the European Commission is examining allegations of anti-competitive conduct, citing a speech Wednesday by Joaquin Almunia, the EU's competition commissioner. Without specifically mentioning Google, he explains "The work is at an early stage." Bodoni tells us what led to the "scrutiny" and the types of things the EU will investigate.

Patrick Stafford provides a thorough look into the "dark side of online marketing" -- black-hat SEO. He runs through the benefits, what can happen if Google determines a Web site uses such techniques, and the gray area of tweaking the algorithms. "Experts say the line between black and 'white' SEO is looking increasingly blurry, with many experts and website operators asking whether certain blackhat methods are now just part of doing business," Stafford writes.

Google's Matt Cutts asks what Webspam projects the company should work on in 2010, garnering comments that are worth an in-depth read. When Cutts asks a question, people respond. More than 135 comments provide insight on everything from Google Chrome Web spam reporting tool extensions, to a platform for junk content, to a duplicate content search engine that helps people identify where their content might be duplicated.

Jill Whalen explains nine steps to diagnosing the cause of lost search engine traffic after reviewing a few sites whose owners saw a drop-off in visitors. For example, she suggests first determining the type of traffic lost. Many people look at Google's overview page, see a loss of overall traffic to their Web site, and assume that they must have lost their rankings in Google and the targeted traffic that comes with it. Whalen tells us this is not always the case.

Ann Smarty tells us about some Firefox screen-splitting tools that enhance productivity. These tools allow her to simultaneously compare search results from a variety of engine; quickly switch between tabs; keep notes, and summarize everything in one window.

Bryan Eisenberg believes some paid search advertisers might be addicted to PPC ads. He makes the comparison from experience as a former social worker who helped mentally ill and chemically addicted adults on their road to recovery. He provides a list of options for intervention to shake the addiction, but if you're in the Boston, Philadelphia, or New York City area next week, you might want to check out Eisenberg's workshop, "PPC Addiction: The Road to Recovery." No joke.