Legality
Although these chemicals were not yet scheduled, a long shadow was cast on their legality by the 1986 Federal Analog Act. This Act and the United States v. Forbes Colorado federal district court case stipulated that the burden of proof, in regards for the intention for human consumption, was on the government if any prosecution under the Federal Analog Act was to occur. Additionally, legal ambiguities regarding the legality of certain analogs of scheduled substances had been established in the aforementioned court case (In particular, the similarities of AET and DMT were debated).
As the Analog Act requires intent that a drug analog be manufactured or sold "for human consumption" before becoming prosecutable, it's possible that the people arrested in this operation could have escaped prosecution had they been more careful in how they promoted and represented their products. Many lapses of judgement or legal knowledge on the part of the web site owners and operators contributed to their downfall, such as the marketing of "sampler packs" containing what amounted to individual dosage units of drugs and aggressive promotion of their wares specifically as psychoactive drugs in various forums, such as Usenet. Usenet readers repeatedly warned at least one site operator that they were going to run afoul of the Analog Law.
Read more about this topic: Operation Web Tryp