I explained this above as it does not appear to be a code issue. I use 5 browsers here IE, FireFox, Safari, Opera and Chrome.
Your links all view fine to me under all browsers.
In fact you can try this for yourself under windows browsers to see what I explained in my previous post. the limit variable is the one that contains the timeframe.
no limit means all ads.
Now using your site as the example if hit last7 I get all ads posted in the last week which was 3 when I last looked.
Now if you go to your browsers pull up the url for last7 in your windows browser your seeing 3 ads. In your apple browser your seeing all ads.
Thus it would stand to reason your apple browser is somehow negating the limit variable in the url. To test this go to your windows browser and take the limit variable off the url. You will see all of a sudden you are viewing all ads. Thus that duplicates your issue of seeing all 10 ads instead of the limit passed.
The only way to get the results your getting would be to REMOVE the limit variable from your url.