5. Google Book Search Scratch and Sniff
According to Google, if you placed your nose close to your computer screen and clicked an on-screen "Go" button, its online library would "load odors" that you could smell. Seriously. Anyone who clicked the button, failed to smell anything, and felt confused probably went to the "Help" section, which redirected them to a page that described the origins of April Fools' Day. Yeah, we smelled something. Bullshit.