At the highest level, nothing has really changed. If you are smart, patient and had a nice reef a decade ago, then you can have one now. Bacteria is still bacteria. Chemistry still works the same.
You might see the absence of books and other vetted sources of information - everybody is a pro now and expected to be treated equal on a message board or online. Be careful who you follow and listen to - just like a decade ago, not all opinions and experiences are equal.
You might see an absence of good LFS or local support, depending on where you live and if you ever had any to begin with.
Like anything in life, there are some things cycling back around that were out of style 5 years ago. Lots of people are using T5s with their LED. MH sales are at a decade high. People are dropping DC pumps for the super-reliable AC pumps - this is good and might cause the DC pump manufactures to up their game and make a reliable pump that will last 5-10 years like AC pumps do.
China is in the market now with cheap things. Not everything from China is junk, but a lot is - just do your research.
Perhaps the most important change for me is that lots of more fish and coral are captive bred.
Probably the largest change is the creature comfort for the reefer. You can have a webcam to view your tank, alerts and monitoring of nearly anything that you can think of (with varying degrees of accuracy). You can change the color of your lights from your couch on a iOS app (you should probably not do this, but people do). While none of this is necessary to run a reef, some reefers really love it and it makes them really happy.