LeadSight currently uses first-touch attribution: all of a deal's revenue is credited to the very first channel that brought that customer to your website.
First-touch rewards the channels that create demand in the first place — even if a customer's final visit before converting came from a different source, like a direct visit or a branded search.
Other models — last-touch, linear and time-decay — are planned, so you'll eventually be able to switch between attribution views. For a deeper explanation of how each model works, see the Attribution Guide.