Letter of intent is used when an individual enters into a certain transaction or business relationship. People usually go for letters of intent instead of going for a legally binding agreement.
LOI is used as manipulation tool at the hands of unscrupulous sellers & agents. Often times, obscure or scam_oriented persons who claim to be crude Sellers, or represent themselves as sellers' agents, mandates or brokers largely by an Internet contact or communication, employ the LOI merely as a tool to quickly "corner and box in" a prospective buyer to a purchase deal, before the prospective buyer may demand that they provide their business profile or show him something tangible to demonstrate that they are truly legitimate sellers. Such sellers would persistently demand that the prospective buyers hurry and issue them an LOI right upfront purportedly as proof that they are "serious" about making the purchase _ that is, before the buyer may probably start raising some probing questions about them or their credentials as legitimate sellers.