Bitcoin Cash is the new fork, and that fork has 2MB block size. Bitcoin (Original) still has the 1MB block size. The reason it is called "Bitcoin Cash" is because it can be used more like cash, because the transaction fees aren't assumed to be as high because more transactions can fit into a 2MB block, which means you and I don't have to put big fees onto each transaction to get into that 1MB block.

The reason they did the fork was so that the fees that were making small (cash like, e.g. buy a coffee, $10 Steam gift card, etc...) transactions impossible, are now cost efficient because there's less bidding wars from people on the network rushing into get their transaction confirmed ASAP.

Super interesting to see how it unfolds, but it appears that there's no network congestion and that the network was getting spammed prior to this fork in a means of "See. See! We need bigger blocks. That's it, we're forking. I'm sick of this."

It can get a little "tin-foil-y" but there's theories all over the place, and a lot of them have sound reasoning, but the tl;dr is /The network forked /Bitcoin = 1MB blocks /Bitcoin Cash = 2MB blocks /Where things go from here is a roll of the dice ;)

Thanks!