Google, then, is populist about art, and tends to point users towards iconic masterpieces. Is there any downside to that? Actually, no. People (critics, curators, "experts") make too much of obscure knowledge and over-refined erudition. Art's greatest hits are often the greatest works, full stop; if you want the basics about Picasso, a glance at Les Demoiselles d'Avignon will tell you a lot of what you need to know.
What's more worrying is the lack of correlation between the immense online archive of art and the even more immense reality. Because so many works can be found online, there's a danger of forgetting how many cannot (not to mention the inadequacy of a picture on your screen compared with the real thing). A student can't really research a dissertation on art from digital sources alone, however tempting the illusion. And there lies the real vice of Google.
Arguably, it's the art world's job to get more (and better) information about art online. For a terrific example of how this can be done, see the IMA's blog post on their project to encourage documentation of Indianapolis's public artworks, Wikipedia Saves Public Art.