This in fact is not new, various groups have had quite sophisticated online tracking for some time. Perhaps the best of the bunch is the UKHAS [1] balloon tracking program which you can find here:

http://www.spacenear.us/tracker

It's open source (of course!) and is run on bits of software contributed by various groups. It integrates with the UKHAS 'distributed listener', where anyone with a suitable radio (most HAMs) can listen in to a balloon flight and automatically decode and upload telemetry to the online map. The sound card software is a fork of fldigi [2] which has been modified to do all the uploading, and is cross-platform.

The UKHAS tracker also makes use of some flight prediction software from the Cambridge University Spaceflight group [3] to give live real-time flight and landing predictions so anyone chasing the balloon knows where to drive.

All of this stuff is FOSS. It's a glorious little cul-de-sac of geeky openness. Happy days!

[1] http://www.ukhas.org.uk/
[2] http://ukhas.org.uk/guides:tracking_guide
[3] http://www.cuspaceflight.co.uk/ (/predict for the flight predictor)

The answer lies in the fact that your assumption is wrong. The vehicle is not used as a conventional crane.

In order to stop the payload swinging like a pendulum into the ground (as we just saw), you need the payload to be right underneath the balloon when you release it. There is usually some amount of wind, even if very slight, and so to satisfy the first condition, you have to have a vehicle at the bottom to drive the payload along at the same vector as the wind, right underneath the balloon which is also moving along with the wind. When you achieve this, it is safe to let go, as the resultant force on the payload should be purely vertically up.

In this case, it was clearly a premature release. You can see the vehicle moving, but it looks like the wind conditions were midjudged, resulting in the crane vehicle having to make a maneuver that over-strained the release mechanism, forcing it to give. As expected, given the very large off-vertical angle between payload and balloon, it crashed straight into the ground.

The documentary 'BLAST!', about a very similar project, is worth watching if you can. The trailer [1] has enough footage for you to see a launch more clearly. Launching these things is not easy, as you can tell.

[1] http://www.youtube.com/watch?v=ebJglJaMBnA

As an asside: yes, I'm new here, but why do people declare things so confidently when it's quite clear they don't have even the vaguest comprehension? It's baffling. There should be some kind of cost function attached to it.