I think that almost every ad I've seen on PPRuNe has been absolutely irrelevant for me because of either product (in which I have no interest whatsoever), or location (directed at people in another country - usually on the other side of the globe). This for me is spam, and I choose to block spam in whatever way is convenient and effective; especially when I have to pay to receive it.
Now if they advertise Amateur Radio gear or Photographic equipment (Canon if you will please), I will certainly show a little more interest.....
FOR