If you really found tags all that valuable, you could start doing them inside comments.

Preliminary report: this isn't going to work, not without drastic contortions in the choice of tags (which IMO kills the effectiveness of the tactic). For instance, from my first set of 30 I tagged a number with the tag "personal", predictions which only concern one user (or two acquainted with each other) and that I don't want to see because I can't effectively assess them. The Google query including "personal" returns close to 30 spurious results: for instance those containing "personal computer" or "personal transportation". (A temporary workaround is to include the term "tags" in the query, but this will cease to work once a greater fraction of predictions have been tagged.)

I doubt you will adopt my suggestion

You are correct about the likely outcome, but I think I've just proven your model of the underlying reasons wrong: I won't do it because it won't work, not because I lack the conscientiousness to do so, or because I'm too selfish to take on an effort that will benefit all users.