Most folks I know pretty much have. But, think deeper. Social networking sites change and morph, but these tactics are available to the operators and now that they are public knowledge, the question is what should be done about it?
Imagine Google shaping the queries you do on their search engine, not just by whom will pay for “placement” but by how they will manipulate your thinking and opinions?
If Facebook was altering feeds in 2012, were they altering news and headlines in favor of the Democrats for the 2012 election?