The SENSE verb allows characters of different professions to determine information about their surrounding areas. Currently, this verb is most useful for Clerics, Paladins, Rangers, Rogues and Sorcerers, although it has been used in the past (and still is, although the reason is now obsolete) for Wizards.
For all other professions, the verb merely gives one a basic, humorous message. "You sense you are not a wizard and thank your lucky stars."
Clerics and Paladins
For those that are close to the Gods, the SENSE verb allows the character to detect the presence of any diety's special presence. If detected, such a presence effects the outcome of a Prayer of Commune. Such a location (called a "holy shrine" permits a Paladin to bond to a weapon via Sanctifying it, or a Warrior to use the Weapon Bonding maneuver.
Rangers are stewards and students of nature, and as such have the ability to gleen more information about the world around them than do other classes. A ranger can SENSE the "nature" of their environs, providing the ranger with useful data about available Animal Companions, climate, and terrain; the latter two are mostly of interest to those attempting to FORAGE.
Rangers can also sense non-obvious paths, or exits from a room, unless they are not supposed to be findable.
Rogues are able to get a sense of "crowd conditions." By attempting to SENSE their surroundings, they are able to get a feel of whether an attempt to STEAL (verb) would be successful, or noticed.
When a sorcerer attempts to SENSE the PATTERN (Syntax: SENSE PATTERN), they will record into their tome a sequence of runes that can be used to Planar Shift (740) back to that room later.
Previously, the SENSE verb informed a Wizard of the relative strengths of any mana pools in the area, which provided a good guage for what sort of Enchanting project was possible, and if one was located in a Wizard's Workshop. With the removal of mana pools from the enchanting system, the verb now simply informs if an area is, in fact, a workshop.