http://www.ea.com/1/service-updates

As of June 30, 2014, EA will end online service for Neverwinter Nights, Neverwinter Nights 2, and the expansions.

Thanks, EA!

What does this mean exactly?

It means that the premium content like "Pirates of the Sword Coast" - which requires authentication - may not work anymore...

I've been assuming it means online multiplayer won't function. I admit I'm not completely clear.

As the multiplayer servers are included with the game, the on-line games are safe. However, the update services will not be available anymore (yet, Gog included the last version, so is a minor problem). The premium modules as @shawne said are a real pain.

The online multiplayer servers were shut down ages ago, and have been entirely fan-run for the last several years. There will be no direct impact here. The two big issues will be patching and authentication of the premium modules. Hopefully there will be workarounds for affected people.

For people with the GOG release, this is only an issue for those who want to play the NWN1 premium modules. These modules are not included in the GOG release precisely because they contain DRM. They will stop working when the servers are pulled down.

Oh dear. I'd best get my stuff authenticated asap.

To be clear I'm specifically talking about premium modules you purchased through the NWN online store. If, like me, the only premium modules you have are the ones included in the GOG release you're fine. Because those three had a physical copy release they do not have the same activation limitations as the later "DLC-only" premium modules. Sorry if I was unclear, I tend to think of the two trios separately for that reason.

It's where Wyvren Knights of Cormyr, Pirates of the Sword Coast, and Infinite Dungeons are concerned that there will be problems. To my understanding these need to validate every time you start the module, so a workaround will be needed for those to keep them from disappearing forever.

Ah. Those ones, to my knowledge, haven't even been available for years, soooo okay. I'm a lot less mad now.

And it means absolutely nothing to people who already run their own dedicated servers for those games.

Time to change of engine:

http://www.nwnpodcast.com/nwnp/2014/04/22/nwnp-podcast-episode-192-xoreos-an-open-source-reimplementation-of-the-bioware-aurora-engine/

http://content.bioware.com/neverwinternights/modules_premium/PiratesOfTheSwordCoast_Installer.exe

http://files.bioware.com/neverwinternights/modules_premium/WyvernCrown_Installer.exe

http://files.bioware.com/neverwinternights/modules_premium/InfiniteDungeons_Installer.exe

They are available, but if you want to play them, you had better do it before the cut off date.

Thanks for the links. I will download the files and make a backup, should the links not work anymore after June.
I also hope that the premium modules will keep being playable.
As far as I know the server for validation has timed out for a while now, so this might not change the playability of the premium modules.
Someone who didn't buy the premium modules could try to download and install the files from the links and test it. If the modules are playable after the server times out, then the server takedown in June shouldn't matter.

edit:
Actually I believe it is only the GameSpy part that is shut down (See here). I believe dedicated servers will still work (connect directly to IP).

The NWN online service was shut down years ago. The dedicated servers have been running entirely independently of EA for some time and will not be affected, so no worries there.

The only issues arising from this will be that people with physical copies will lose the ability to patch, and the three DRM-laden premium modules (Wyvren Knights of Cormyr, Pirates of the Sword Coast, and Infinite Dungeons) will cease to function.