Trying to figure out the difference between Anmelden, Eintragen, and Registrieren
Native speakers, what is the difference? As far as I can tell...
(1) ANMELDEN can mean to "sign up" or "log on" (like onto a website), as well as register or enroll.
(2) EINTRAGEN is more like "fill out" or "put down," so it can also mean to enroll or sign up, but its more like putting your name down on a list.
(3) REGISTRIEREN can also mean enroll, or sign up, but it usually more like register in the sense of registering feelings, thoughts, etc. E.g., "I registered the pain."
Is that mostly right?
Well, there's really no strict distinction and sometimes they're all used together like: "Tragen Sie ihre Daten in diese Felder ein, um sich zu registrieren oder klicken Sie hier, um sich anzumelden, wenn sie bereits einen Account besitzen!" Especially the Anmelden/Registrieren combination is VERY common on webseites.
(1) Anmelden: You're right. Online, it's mostly used for logging in when you already have an account. Offline, it's more like "sign up" but less formal than "registrieren".
(2) Eintragen: Completely correct.
(3) Registrieren: Mostly used online for "sign up and create an account". Offline, it sounds quite formal and wouldn't be used if you sign up for a sports club. But it's kind of popular to use it in a passive way: "Ich habe mich registrieren lassen." (as an organ donator or something similar).
I rarely encountered it in the sense of registering feelings. It sounds very stiff and disconnected from the feelings! A bit like a robot that has feelings for the first time and tries to analyze them. "Spüren" ("Ich spürte den Schmerz.") would be a more natural way to phrase it.
(1) Yes, sign up, log on, register, enroll, all are possible. It is by the word not possible to determine what is meant: A first-time sign up or a log on, so it should be avoided.
(2) Yes, but using it for enroll or sign up would be a bit strange (but not impossible).
(3) Both meanings are equally possible. In my opinion sign up is the more common usage, registering a pain sounds a bit unemphatic. But both are possible: http://www.duden.de/rechtschreibung/registrieren As this can't mean log on it is the better choice.
For log on we often use the old ancient German word einloggen.