Previously, you uploaded your raw data files from Family Tree DNA, 23andMe and, very recently, AncestryDNA. You received a kit number for each upload, and could plug that number into the different tools to get results. The system wasn't very efficient and I had a long list of numbers to keep track of.
With the upgrades, Gedmatch now requires users to set up accounts. When you set up an account using the same email address you used when you originally uploaded your kits, all of those kits are automatically added to your account. Now, when you go to run a report, such as Admixture, you still have to type in your kit number - but now they are listed on your main login page for you. I would love to see another upgrade that puts your kit numbers into a drop-down list for more efficiency. They do say that the creation of accounts will allow them to "add some new functionality," so I'm looking forward to the future.
Gedmatch is not currently fully functioning, due to the server errors, but I'm really excited about this upgrade. I think it's a good indicator of where Gedmatch is headed: a more user friendly site that's working to make great improvements.