I have to say that my posts on 3 and 4 August were not really sufficiently interesting to warrant that sort of attention, and my first thought was that perhaps a link to an old post - maybe, I flattered myself, the series on the Bloody Sunday report - had found their way onto some very populous but closed online community (a number of obvious possibilities occurred to me), and been widely shared around there, though with nobody leaving any comments.
But I do not think this is the case now, after checking the time distribution of hits over the two days in question:
Looks to me like this must have been a bot of some kind, passing by three times in just over 24 hours. Some new search engine, gearing up for a launch, perhaps? Has anyone else noticed unusual activity of this kind around that time?