At least read the link that was posted? Because otherwise, you miss parts like this from the linked article:
"This is the ideal height because Air density is 1/10th of what it is at Sea level. This makes the wind at these altitudes 10 times less potent."
No, independent of whether it's possible to make a geostationary balloon, Google's balloons are not going to be stationary. They are steered purely by changing altitude and riding high-altitude winds.
Sure, except, the context of this sub-thread was started by someone claiming that winds in the upper atmosphere "can be very fast." So the link was to correct/explain to them, not to claim that the Google Balloons would be stationary.
Stratospheric wind speeds are very fast. Look it up if you don't believe me. I was just basing this from a quote in the original article "wind speeds as high as 291 km/h".