Ads do not cause lag: They are too small a file size. if your computer lags when loading AG, it is most probably your computer, as everything but the games is simple HTML and very small. Or (Although unlikely by today's standards) it is your internet. have both checked.
If you feel reaaaaaaalllyy annoyed by ads, get an adblock. And don't use IE because it seems most ads pop up on it.
1) Ads bring in revenue. You block them, AG gets less money to use on maintaining and improving the site. You do realize that the reason this site is free is because of those annoying ads.
2) The lag must be your computer. Here's why. If you have Google Chrome as your Internet browser, it will tell you what it's loading on a bar in the bottom right or left of the window. I've watched that bar when my computer was lagging, and the majority of the loading was "Waiting for cache...". Whenever it flashed to "Waiting for ads.doubleclick.net..." it only stayed there for a split second, then went back to the caches. You know the "Popular games", "Web games", and "User ranking" sections? I think those are all run by caches (quick data references), and your computer must get the data from those caches before it can display anything on the site. The lag is caused by the amount of information on AG, not the ads.
So, to recap. Ads = annoying, but good. Problem = your computer.