Yesterday evening I got a nice email from Continental Airlines inviting me to check in online for my flight the next day. Nice, I thought. I can save a bit of time at the airport. So when I clicked through to the reservation link in the email, I was greeted with a rather stern message headlined “Unable to complete check in”. The body simply said “We are unable to complete your check in at this time. Please proceed to the airport for assistance.” Thinking that perhaps the system was temporarily down, I tried again this morning – same thing. Now this is a return flight of a round trip purchase, so the airline obviously knows who I am and that I traveled with them Monday to get to my destination. Don’t do this to your customers. On the Web, don't promise something you can't deliver. It doesn't matter what the problem is with their technology - Continental Airlines must not offer something online and not follow through with the promise. It is better not to offer and just let me check in at the airport as usual. This frustrating experience makes me less inclined to fly this airline in the future.