Actually you cant compare all those sites they are using vastly different versions some very old.
Like in 7.0 series the searches are indeed searches which means the results are handled via a search like so http://www.yoursite.com/galleri/sear...term=d&cat=all
That takes you to http://www.yoursite.com/galleri/sear...searchid=67773
There is no limit passed in a url this is for SEO
reasons so you things may not work the way they did in previous versions.
Like for instance in PP8 you will see even more difference because none of that stuff will matter. There will be a java script etc that will cache results most likely photos from a query there will be no additional variables like limit etc.