This is The New Yorker’s online presence for their enormous repository of cartoons. You can search by topic or by cartoonist and browse online through hundreds of cartoons. Yes, the site is very commercial and exists mainly to hawk their multiple lines of prints, t-shirts, et al, but the cartoons are there, large enough to read, whenever you need a little sophisticated absurdity.
If that isn’t enough, there are the occasionally wonderful New Yorker covers, viewable slightly larger than the cartoons. Unfortunately, there doesn’t seem to be any sign of the often great little spot illustrations that have brightened the magazine’s pages over the years. Some of the original art is for sale, although they don’t quote prices on the site.
Of course, if you’re really into New Yorker cartoons, you have the book.