Interesting. I'll sound like a conspiracy theorist but:
There will be elections in 2014, in many political (new President + municipalities*) and money related sectors, probably someone is planning some other -games- to play, to win. Or worse, information manipulation could be used for this, rearrange the ads for different demographics and related IPs of the area...
*Unfortunately municipalities are the main money makers for the governments in here. Money related sectors are, importers / exporters / producers... big companies, sometimes international.