Feel free to add your thoughts..
Playing DnD for quite a while, and now having played DDO I thought I would list some similarities and differences....
1 - while playing pen and paper we would all stop while trying to get our stoned friends attention to roll 'to hit' something....now in DDO we just watch his toon stand there and grunt as he is hit over and over again... Wish we could do that in pen and paper to him.
2- in Pen and paper we always blamed the dice for being unlucky and bought new ones, now we just blame 'lag' for dying, no matter what really happened.
3- only the DM used to know what was behind the door, but the party always knew when to let the 'new guy' open it...... now the whole party knows what is behind the door and lets the 'new guy' open it...either way, funny stuff.
4- pen and paper had different dice...in DDO we only see the d20.. Would be nice instead of seeing '-3' to damage we saw a 4 sided die with the -3 on it.
5- Beholder - Pen and Paper - OH MY GOD!!! RUNNNNN!!!!!!!
DDO- level 10 cap - OH MY GOD...RU <disintegrate/death>
DDO - Now - <finger> Where?
6- Mind flayers
Pen and paper - 'I hate psionics!!!....what are psio..? <dm: your brain just melted, you're dead.>
DDO early on - 'I'm stunned, he's sucking my brain dry!!! Help>
DDO later - Hey, respec me fred!!!
7- Halflings
Pen and paper - "yea, sure bilbo, go attack the dragon...you are dead, this ain't the hobbit"
DDO - "hey, warforged, get out of my way I cannot see past you"
8-
PnP - That DM is such a monty hall campaigner...yeesh,
DDO - LOOT LOOT LOOT.. + 30 to ac with magics, immune to everything, vorpals!!!! One 'bahillion gold pieces!!!!'
......