I recently purchased two tickets from Deutsche Bahn to travel from Berlin to Amsterdam and printed online tickets. Can anyone tell me if I need to stamp or validate these tickets in some way before I board the train?

No, the conductor validated them on th train, but hopefully others will verify..have a great trip.

gregeva1 is correct.

Only thing to remember is to have that credit card with you which you used to purchase the tickets.

Yes indeed about the credit card.

What Cowboy says is dead on.

Your credit card is your ticket ID, not your passport, as far as the train ticket taker is concerned. He will read the printed ticket with a hand-held scanner, and then ask for your credit card to compare the numbers.

Exactly.

Again: Remember to bring the very same credit card you paid the tickets with.

Thanks everyone for your responses. As usual, great and handy information.

Is there validation in general for Germany? I seem to recall facing this problem in February.

I think I was looking for a machine, and I couldn't find any. I think that I was going from Baden Baden to Strasbourg, so I just got on without validation. But I could be wrong about the destinations.

I recall having to validate Strip Tickets on the U-Bahn and the S-Bahn, but I do not recall validating a ticket before boarding the train. A conductor came by and punched the tickets the old fashioned way.

In Switzerland and Austria I don't recall validating either. Last summer in Switzerland we did not.

In France, you do. I was told to find the machine and "composte" my ticket.

Yes, I validated for "local" transport in Germany as well. Esp. in cases when I bought a 24h or 72h or whatever ticket.

Many tickets in the local Verkehrverbünden (transit districts) have to be validated. You can tell these tickets by the words "Hier entwerten" printed on the end with arrows showing the direction to put it in the machine. On the other hand, many tickets in Munich, those sold at DB automats, had the date and time printed on them and did not have to be validated. These tickets were too wide to fit in the machine.

I bought tickets from Deutsche Bahn, but am traveling from Florence to Munich, so boarding in Italy. Does this same information apply? Does the ticket need to be validated before boarding in Florence?

In Italy, all non-train-specific tickets have to be stamped. Train-specific tickets do not. If in doubt, better stamp it.

can't hurt to stamp it right?

generally in many countries but not sure about Germany if it's a fully refundable ticket you have to cancel it yourself before boarding

In France there is an announcement in French to this effect on trains i've ridden recently about those boarded who have not canceled their tickets before boarding to find the conductor before he finds (and fines) you for riding without a valid ticket

refundable tickets often must be canceled to prevent them being refunded as on some trains there may be no conductor come by, etc.

Discounted train specific tickets that cannot be refunded or used on other trains do not generally require canceling before boarding IME

In Germany, you do not cancel regular (long-distance) train tickets, no matter if they are fully refundable or for specific trains/times.

Only when you travel in local transit areas you are supposed to validate your ticket - which would look very different and be much smaller to fit into the stamping machines. Just imagine if you had fold your online ticket until it would fit in the slot of a stamp machine in Berlin ;-)

That's why you cannot buy some tickets for regional trains via bahn.de's website (e.g. for traveling from Munich main station to Munich airport) - because both stations are in a local transit area, and you have to buy (and stamp) the tickets from the local transit authority's outlets (even though Deutsche Bahn or a subsidiary runs the trains).

Rule of thumb for Germany:

Tickets on which the date and hour of validity is printed do not need to be stamped and validated.

Example: train ticket - "Gültigkeit 28.4.2008 - 27.5. 2008, Hinfahrt bis 29.04.2008" (validity 28.4.2008 - 27.5. 2008, for the otward journey till 29.04.2008)

Example: tickets for local trains or local transport from ticket machines. Check if date and hour are already printed on it ("28.04.2008 14:35", this is/should be the exact time you bought this ticket), usual with something like "Zum sofortigen Fahrtantritt" (for immediate begin of travel). If yes: fine.

If date and time are NOT printed on it and the thing has a field with an arrow on one side, it is meant to be stamped to be valid. The period of validity begins with the time the ticket validator stamps on it.

If in doubt, ask someone. If there is no one to ask, better stamp one time too many.