No, you make a single account and subscribe to the communities across whatever servers you want. The exception would be if the server you registered and the server hosting your desired community had become intentionally unfederated/disconnected, but hopefully that doesn’t happen too much. The third-party apps (like Memmy) are making the UX more seamless with subscribing to communities across different servers.
I was having major issues getting federation to work while using the mobile web app. Now that I installed Connect for Lemmy (android) tonight, I finally have a seamless experience subscribing to and interacting with communities from all over the fediverse.
It's a brand new technology and system, for the most part. Give them time to make it more user-friendly. It's worth it joining and participating now IMO, but I think in 6 months or a year it will be MUCH more friendly to the average Joe.
Lots of the Reddit apps are being ported for Lemmy as we speak so it's about to get even better and easy to use.
At the end of this all, the biggest mistake that Reddit will have made may be sending all the most talented devs creating apps for their platform to their direct competitors.
