I have been thinking for some time about how much easier this could be for John if a set of downloadable tools were available at first signup. One example would be a right click option on a thread to set preferences for how you wanted to be flagged or if you wanted to have the thread hidden from you so as not to be bothered. Another would be a "flag me when this FReeper posts" option when right clicking their name. These would greatly reduce the random looking around.
My guess is that these could be marketable products that John could sell as a separate business. All it would take is a link to a separate page. It would at least be a way for the Robinsons to profit by all this valuable work. Why not make it available as a general set of "Chat Room Tools"?
I still don't understand why a thread isn't loaded as a series of separate records into a temp file so that one only need append it. I guess that is a limitation of the browsers.
Those are some interesting suggestions that could be incorporated into the preferences page. A quick note to John might result in his adding them in.
Be sure to exlain them well, so there's no doubt about what you're trying to accomplish.