Just the other day someone asked me "Do you believe [in God]?" I replied "everything is technology". I referred him to just this type story. Speech is technology. Writing is technology and therefore stories are too technology. Everything we hear or read from man is manmade. He paused and thoughtfully said "I never thought about it that way."
What just happened? I search for a park I visited just yesterday. "186" hits(?) and two of those were two top page HN sites I just visited!? I'm spooked.
A Google Doc, shared would also do the trick. I was first thinking EtherPad and I did that for years in-house but then I realized Google Doc is just that only better as I didn't have to add plug-ins to get images. See my other comment for what I do myself, professionally.
We're a 24 person department; not a startup but we act in some ways as one. I am the in-house tech person and I use a database to record each days work. It's for myself but I know it will be valuable to the person who follows me so it it very detailed. I have a daily backup of it and occasionally make it a PDF just-in-case. I know this doesn't address your overall need. If I were to do that I'd just make mine shared with the group and have them do entries as well. It would be a time-line sort of documentation I guess but still super valuable.