Some of the problems you list may be specific to your situation, i.e., the particular server you end up on and/or particular browser you are using, etc. The 20% figure is NOT consistent with my own experience at all. I would say the site is down maybe 1-2% of the time, and I access it very frequently.
E-upgrade summaries work for me most of the time, but not always. I certainly wouldn't claim they "haven't worked for 2 months."
I doubt that a b*tch list posted on a website is going to make a huge difference to United. These problems are not just ones of motivation, as the posts here seem to imply; there is a huge amount of work involved in maintaining any complex system, and undoubtedly limited resources to do it. Some of the problems may be outside United's control. I too wish they would fix all the problems and add all the new features we want, but none of this will ever happen overnight. Also, since some problems are intermittent and only occur under certain circumstances, it can be hard to diagnose what the problem is without more details. But instead of providing details, these posts just pile on a bunch of generalities (like the 20% downtime figure, the features that supposedly "never work," etc.). These kinds of generalizations are not really useful for actually fixing anything.