IMO, pumping and bashing on stock forums is an integral part of stock trading. Depending on the situation and stock status, the pumper buzz or basher stings can point what direction the expectation for the stock's pps is heading. I'd dare say this pump and bash strategy can have dire effects on pps. Forum discussions help spin info in different ways, not all is simple pump and bash.
SEC investigations have used forum posts as evidence, though the info is unregulated as you stated. Do an Internet search and you'll read much about this topic. Read the SEC website topics.
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