Just an observation... I'd expect other Toyota car ads or possibly other hybrid makes, but not Audi/other non hybrid/'green' makes. Weird.
Why do some television networks advertise their programming on other networks? Because they have money and one can not have too many sponsors.
This site does not choose the ads, a middle-man (like google) does, placing car ads in car websites amongst other places. Posting a thread with the 'A' word just increased the chances of more. LOL
Danny funds the site via ads. Maybe Audi was high bidder? Maybe it was their turn in rotation? Maybe you had been to an Audi site lately and Google is targetting your ads?