Complex sentence: Shilling is illegal in many circumstances and in many jurisdictions because of the potential for fraud and damage, however, if a shill does not place uninformed parties at a risk of loss, but merely generates "buzz", the shill's actions may be legal.
Split into simpler sentences: Shilling is illegal in many circumstances and in many jurisdictions because of the potential for fraudulent and damaging character of the shill's actions. However, if a shill does not place uninformed parties at a risk of loss, but merely generates "buzz", the shill's actions may be legal.