[JohnTHaller]

On Windows it's incredibly bloated and has really bad UI design. Apple always used to trick people into installing Safari and Quicktime bundleware-style during updates as well. (Source: Every computer I've maintained over the years and asked the owner 'why did you install Safari' and the answer is always 'I guess iTunes did it')

[yuhong]

I believe iTunes formerly required QuickTime.

[JohnTHaller]

It did years ago, but hasn't in a while. Since then, Apple Update would pre-select to install Quicktime and Safari when you updated iTunes unless you purposely unchecked them each time.