We like to see how other people go about planning their trips. We glean ideas for our own and we identify with the trials and tribulations of others' plans. It's fun to read pre-trips from those going at the same time to see what other people do in the same circumstances.
I use my pre-trip as sort of a journal of my trip. Years from now, I forget what all I went through to get to WDW and it's very fun to go back and read it. I copy my posts and put them in my scrapbook. No one else will ever read that stuff but me, but I love it anyway. Maybe it will help my kids someday when they have trips to plan for my grandkids! Ok, that's a little over the top, but I can dream.