Therefore, as chip leader, you should aim to play tight in the preliminary stages. You should only start opening up your aggression when antes are involved (more chips to steal and take advantage of) and/or when players will have to play a bit more straightforward from being shorter stacked (i.e. 30bb or less).

The player with the most chips at any given point in time is known as the chip leader.  This title will often change hands many times over the course of the tournament, and it has more significance in the later rounds than it does at the beginning of the tournament. Having the chip lead is important for many reasons.