I asked about this term once and get a lot of spam about scamers and shitcoins. so what i get from the web and community:
Bitcoin was really innovative and powerful thing not without their flaws. some of them were not obvious and were not immediately clear. There were first clones of Bitcoin (Litecoin and etc) - 1st generation of alternative cryptocurrency's. They did not to improve correct congenital defects but simply offer something new.
Now after few years after start the massive use of BTC some peoples believe that some of the shortcomings that are critical enough to correct them:
- BTC have high entry threshold into the mining. not for union users with laptop's
- BTC is not true anonymous (once you create an transaction - your balance can be tracked in blockchain)
- BTC are bad for the environment (it's the point about electricity. of course BTC less then fiat but as a phenomenon of the 21st century it's pretty much)
- some other disadvantages about Proof Of Work Bitcoin system
So there are need of new currency's with new ideas devoid of these shortcomings. There are a lot of altcoins. There are a ;ot of scammers in altcoins.
I will not name concrete coin. I dont know wich one will rise.
But i trust that there are some coins that can be named "next gen" - true anonymous, fast, ecological, easy and honesty. Just try to find one for yourself