A lot of programs–especially free ones–install additional software on your PC. They do this as a form of advertising, and they may make some money off of it. Of course, it can backfire and alienate users.
This practice gives you, the user, an additional responsibility. If you’re not careful about how you install freeware, you can end up with a lot of potentially unwanted programs (PUPs).
(Frankly, giving what we’re talking about, I find that acronym way too cute and cuddly. The acronym would have been far more descriptive if everyone had agreed on the term “potentially unwanted software.” On the other hand, these programs leave messes all over your PC, so perhaps PUP is appropriate.)
But why don’t antivirus programs block PUP-carrying installers? Because they’re legal, and because, annoying as they are, they’re not anywhere near as bad as real malware. True, installing one program and getting two or three more feels like a violation, but these unwanted programs don’t hide their existence. Nor do they, as far as I know, do anything illegal. And they can all be uninstalled.
What’s more, in almost every case, you can install the program you want and bypass the PUPs. You just have to pay attention while installing .
First of all, never, ever select the “Typical” or “Automated” installation–which will almost certainly be the default. Select the Custom installation or a similar option.

iLivid installation. Select the settings that the arrows point to.
Then, study every page of the installation wizard, and uncheck every option to install another program (unless, of course, you want that program).

More of the iLivid installation. Select the settings that the arrows point to.
You can’t really blame the developers for wanting a little money for their labor. But you don’t have to install software that you don’t want.
via Why isn’t a program malware if it installs additional, unwanted software? | PCWorld.