Though I hadn't seen anything that extreme when I lived there, I did have to sweep away spider webs from our shrubs every day in the summer months. If I'd left them, they may have ended up like those images.
I've never seen anything like that Pappy...however I do know one park was covered in spider webs a few years ago, but I have not read of anything since.
Those photos are extreme examples of what happens when the ground is waterlogged. The spiders move up to higher ground and congregate. They still have to eat so the trees become festooned with webs. I think I posted a photo of an assortment of spiders on a bridge during floods at Richmond, near Sydney.
This is the photo in question. The flood water rose above the deck of the bridge and the spiders kept climbing.
Personally I have never seen this happen but there are some spiders on Norfolk Island that live permanently in colonies over and between the bushes.