A lot of stealing goes on in poker, and the most common form is when a player bluffs pre-flop – often in an uncontested pot – with the aim of stealing the Small and Big Blinds.
This play tends to be most executed from late position and is indeed positionally oriented, the point being that the steal is more likely to succeed with more players having already folded.
Stealing the Blinds is an integral part of the game, and a key weapon, particularly in a tournament setting. This is because as a tournament progresses the Blinds increase, which in turn leads to progressively larger uncontested pots. Note also that at some point in a tournament Antes are introduced, thus adding more chips to target with a steal.