I don't really think they are vibrations (or resonance) in the suspension. Or bumps in that specific part of the track. Just because we could see those skid marks at least in other two places:
http://sia1.subirimagenes.net/img/2013/06/16/13061608333271523.jpg
http://sia1.subirimagenes.net/img/2013/06/16/130616084341460936.jpg
As far as I know, both images come from the warm lap.
I'm far from being an expert but I always thought that suspension resonance is too rare to be happening that often. Furthermore, all that resonance (or even if the car was boucing) would mean that the suspension, ARB and/or dampers of the car causing all those skids were not doing their work. Which I find almost impossible considering there wasn't even one DNF caused by suspension in that race (as far as I can remember). And we're seeing F1, not stock cars.
Yes, there is longitudinal as well as lateral oscillations of the chassis in F1 cars. But that is: the chassis. The suspension, ARBs and dampers are made so that wheels touch the surface as much time as possible, even with the chassis oscillating really bad.
Even really big jumps (ie, crossing curbs in a really aggresive way), that cause the car losing contact from tarmac, usually lasts about two jumps. Here we're seing more than 10 skids, the rear right even caused about 4 of those skids before the tarmac change, although they are far less noticeable. And with the closer curb at a few meters I can't see oscillations causing that.
And yes, TC would prevent the wheels from sliding and there would be no skids at all. But we can't compare electronic TC in normal cars because electronic systems like the ones in ours cars are simply banned from F1.
If any of the F1 teams was considering to "emulate" a TC, they should be doing it somehow more mechanically with the less electronics involved in it. Remember that, for instance, their differential is mechanical, not electronic (correct me if I'm wrong).
With that I mean that a team (Red Bull in this case, but you name it) with a TC, would have a very rudimentary though smart system. TC is not only negative ABS, there are other ways: some kind of engine mapping, somehow turning off cylinders, etc.
Anyway I don't think it's a traction control.
I actually don't know what is causing that but I really believe it has nothing to do either with suspension or a bumpy track.
That would mean Webber's suspension and/or dampers were not working well enough to do 70 laps.
I'm a bit more convinced it has something to do with differential. That's why only right rear wheel make those discontinuous skids before the tarmac change).
And maybe the clutch is also involved. And that's why we have only seen those skids unders "special" circumstances like the start of warm lap (first photo I put), a presumably burnout in the warp lap also (second photo I put) and a start from "near zero" after a collision with Van der Garde (the abovementioned video).
Webber is well known to make a let's say "poor" use of cluch in the starts compared to others.
We could see him, relatively often, losing two or three positions just before the first turn due to sliding in the start.