It's insidious. I worked IT at a nonprofit that cares for disabled people, and every so often I'd find that OneLaunch toolbar at the top of one of our PCs and have to go in and uninstall it. I'd look in the history and see that one of the care personnel googled something like "printable calendar" and got tricked into clicking one of those ads. I don't know how google expects you to use the Internet without blocking all that shit.