Welcome to the world of FFXIV RP (and MMOs in general)! I hope you have fun and enjoy your stay! I am not too certain on the amount of RP on Brynhildr and Siren, but I definitely know Mateus is a known RP server, so the one you have there will likely be able to find a decent bit of RP! Hopefully you'll find some on the other servers as well, though.
As for the various acronyms...
ERP and E/RP are the same thing, yes. Erotic Roleplay. However, there's a couple others as well:
*MRP or Mature Roleplay, which CAN include ERPish elements, but is also for more mature scenes and interactions in general. Along with that is also...
*DRP or Dark Roleplay, which is also more mature roleplay but focusing more on darker elements like torture and other such things.
Those are the three "types" I usually see flagged to identify what sort of RP people are willing to (or want to) delve into with their interactions.
Another pair you might see (and you've mentioned one of) is WU/T. Those simply mean that the player is open to Walk-Up (WU) RP or being sent a /tell (/T) to be engaged in RP.
There are a few other shorthands and acronyms I've seen, but they're usually with an ERP tag, and are quickly identifying preferences in that sort of RP. If there are any others I might've missed though, feel free to mention them and I'll let you know if I know what they mean.
As for the various acronyms...
ERP and E/RP are the same thing, yes. Erotic Roleplay. However, there's a couple others as well:
*MRP or Mature Roleplay, which CAN include ERPish elements, but is also for more mature scenes and interactions in general. Along with that is also...
*DRP or Dark Roleplay, which is also more mature roleplay but focusing more on darker elements like torture and other such things.
Those are the three "types" I usually see flagged to identify what sort of RP people are willing to (or want to) delve into with their interactions.
Another pair you might see (and you've mentioned one of) is WU/T. Those simply mean that the player is open to Walk-Up (WU) RP or being sent a /tell (/T) to be engaged in RP.
There are a few other shorthands and acronyms I've seen, but they're usually with an ERP tag, and are quickly identifying preferences in that sort of RP. If there are any others I might've missed though, feel free to mention them and I'll let you know if I know what they mean.