If any U.S. issuer is placing securities without formally registering the flotation, the offering must be private and exempt, meaning in turn no "general solicitation." According to the letter of Regulation D, the Securities and Exchange Commission's safe harbor for exempt private offerings, if the market for the placement is conditioned by "general solicitation" — classically a newspaper interview or puffery on a public podium — the placement is illegal unless registered. Violations can have serious consequences for issuers, agents and lawyers, and unfortunately, the entire area is in a muddle as of this writing.
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