  High resolution radio observations remain the most direct way to study the
formation and evolution of radio jets associated with the accretion onto
massive black holes. We report preliminary results of our seven year VLBA
observational program to understand the nature of relativistic beaming in
blazars and the surrounding environment of massive black holes.
  Most blazars show an apparent outward flow away from an active core. However,
in a few sources the motion appears inward, most likely the result of
projection of a curved trajectory which bends back toward along the line of
sight. The apparent motion of jet features is not always oriented along the
direction separating the feature from the core, and in a few cases we have
observed a clear change in the direction and velocity of a feature as it flows
along the jet. In other sources, the motion appears to follow a simple
ballistic trajectory. We find no simple relation between the time scales of
flux density changes and apparent component velocities.
