Most easements fall under one of two categories: affirmative easements and negative easements. As will be discussed below, the key difference is whether the person holding the easement right is allowed to do something (affirmative) or required to n ot do something.
An affirmative easement gives the easement holder the right to do something, and requires that the property owner do something -- such as allowing another access to or across a certain piece of property. Most easements fall into this category.
A negative easement is a promise not to do something with a certain piece of property, such as not building a structure more than one story high or not blocking a mountain view by constructing a fence. There are not many negative residential easements in existence today as such architectural specifications are typically covered by rules and regulations promulgated by homeowners' associations. These documents are usually entitled Codes, Covenants, and Restrictions, often referred to as CC&Rs. A negative easement is sometimes referred to as an easement of light and air, and in most states cannot be created by implication.