I just applied for a job using this system, and it really needs improvement.
First, I'm using Firefox with Adblock Plus, and the "Cover Letter" dialog does not function. I had to switch to IE. :shudders:
Next, I selected "use my Stack resume" and it opened a frame that could not be re-sized or scrolled. My information didn't fit in the window, and even unselecting sections didn't help. I changed it to upload my resume.
The next flaw was that my cover letter was reformatted without any line breaks. I had to edit it and add double lines to get a line break. These were then left as double line breaks. It was truly odd behavior.
For a career website that caters to the best of us, I'm shocked to find flaws like this in the presentation. I'm honored to be part of Careers @ SO, but I really expected such an important part of the process to be smooth and flawless.