I had also missed the 'Your report history' link, but I've started to report spam from the Bitcoin Discussion topic 3 days ago (with nearly 0 report count that time). I haven't really paid attention for the number of the reports so close, so I can only guess that the magic number is somewhere around 300 reports, because today I'm over 300 and the 'Your report history' link has appeared. It's good to see which posts were reported in vain...
Strange number, but I guess it's been implemented to prevent those who only report now, and again from moaning about their reports being bad. Seems to be working so far as I've not seen any complaints.