  A discussion on the viscoelastic properties of weakly attractive colloids and
the relation to a newly developed percolation theory is presented. The need for
taking into account the particle-particle bond lifetime in order to compare
rheological and percolation estimates of the sol-gel transition is stressed.
Recent molecular dynamics simulations and generalised percolation theory that
use a bond lifetime criterion in the definition of aggregates show that the
percolation transition can be reconciled with the rheological sol-gel
transition. The percolation concept is used here as a "measuring" tool to
assess the viscoelastic behaviour of the system.
