Chrome, and Google's Position on Browser Privacy
Google Chrome, being the dominant web browser in most of the world, has taken a few hits lately in the privacy department. Between adware-filled extensions and microphone-listening exploits, It might look like Chrome has privacy problems. However, both of those issues are third parties using a combination of built-in features and user trust to spy on them—it has nothing to do with the browser itself. We'll get to how third parties play into things a little bit later, but first, let’s talk about Chrome on its own.
Like most browsers, Chrome has useful features that phone home to Google or use Google services. If you sign in to Chrome with your Google account, you can make use of Chrome Sync, which lets you sync your bookmarks, passwords, and tabs for later or to use on other devices. Logging in to Chrome also lets you use Chrome Apps, and while you don't have to sign in to install add-ons, Google definitely encourages it.
Opera also has an advertising division, if I'm not mistaken.