Protests can be effective if they're well-organized and there are people there to get names and contact info from protesters so they can be called / emailed later and kept motivated and politically active for other events and campaigns. If it just ends up being people getting together, marching, and then scattering afterward, then it's more or less a waste of time. For example, as much as I dislike the Tea Party movement, they were very disciplined and were effective at targeting their efforts to achieve the maximum political impact. I think a lot of liberals spend too much time focusing on the big, shiny objects like marches, and not enough on the less sexy stuff like attending neighborhood meetings, voter registration, and phone / door-to-door campaigning.
Hopefully with everything that's transpiring and will probably transpire these next four years, we get people more interested in the political climate of their countries, especially since it was a worldwide march.
