@travger - there is an easier way without sacrificing readability. Just go to Preferences->Searching, and make sure that "comments" is not one of your searched fields in the "Limit the searched metadata". I petitioned for this feature many aeons ago for precisely this reason and chaley was kind enough to implement it.
In my case I was getting grumpy with typing an author name and having books come back in searches which were unrelated just purely because that name was mentioned in comments for some other book. Now that is no longer an issue - my searches only cover the "tittle, authors, tags, series" columns. And if I ever do need to search comments (which I never do) I still can - I just type comments: before the search term.
BTW please don't feel like you have to justify using it the funky tag approach - as I said to unboggling if it rocks your world then go for it. However I was just suggesting it is not a "recommended practise" to newbies which is where unboggling is targeting his guide. In around a year of using the Calibre forums daily this is the only thread that I have ever seen such an approach discussed (beyond some single digit tags to support earlier versions of the catalog feature). Hence I consider it a "niche" rather than a recommendation - but hey if it works for you, go for it
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