Delta.com is horrible!
I have always booked my flights online for the past seven years. In fact, I can't remember a time where I called the DM line for assistance. However, over the past week I've had the following experiences:
My e-ticket has been completely erased from my record after I checked in for a flight. This presented a big problem when boarding the plane, and required an extra 15 minutes at the gate to fix. The gate agent said it was removed from the website???
My Trusted Traveler info was erased, along with my SkyBonus # for all of the travel I have currently booked over the next few months. This took a DM line rep about 20 minutes to re-enter for me.
Today, I was unable to book a trip for me and my two sons to EWR using the online booking system. It failed because it said that two passengers couldn't have the same first name (my oldest son and I). We have different middle names but that didn't matter. So, I had to call the DM line to arrange the booking. She apologized and said that they were experiencing a lot of problems with the website.

I love DL for traveling, but can't stand the website issues.