The primary difference between the two viral types is in where they typically establish latency in the body- their "site of preference." HSV-1 usually establishes latency in the trigeminal ganglion, a collection of nerve cells near the ear. From there, it tends to recur on the lower lip or face. HSV-2 usually sets up residence in the sacral ganglion at the base of the spine. From there, it recurs in the genital area .
Even this difference is not absolute either type can reside in either or both parts of the body and infect oral and/or genital areas. Unfortunately, many people aren't aware of this, which contributes both to the spread of type 1 and to the misperception that the two types are fundamentally different.