finger - good to see who is logged in, or idle (have not typed). Yes this can be used to see if someone is slacking off

user@example.com [~/notes]% finger
Login Name Tty Idle Login Time Office Office Phone
gregg ttyp0 1d Jan 5 20:04 (ppp-65-139-123-221.dsl.mabell.net)
gregg ttyp1 Jan 9 17:15 (ppp-65-139-123-221.dsl.mabell.net)
gregg ttyp2 15:08 Jan 9 23:44 (ppp-65-139-123-221.dsl.mabell.net)