The real privacy problems don't come from the browser itself, but from the third-party tools and sites you visit. 

Google has other ways to obtain the data they want—they have Gmail, your Google Search history, YouTube, Android app install history, and anything else you can see on the Google Dashboard. Most web companies use persistent tracking cookies to collect information about you, which is far more efficient. Sure, browser developers could do more to protect your privacy and security, but no amount of sandboxing or add-on review will stop users from being the weak link in the security chain, or stop disreputable developers who use TOS loopholes to publish adware in the first place. 

Everyone's Trying to Track What You Do on the Web: Here's How to Stop Them It's no secret that there's big money to be made in violating your privacy. Read more 

As always, we recommend that you get the best privacy-protecting add-ons for your preferred browser to keep your data safe while you surf the web, and to pay attention to the permissions of the add-ons you install before you install themto make sure they match up with the features you expect. If we had to give any kind of edge to anyone here, it would have to be to Mozilla—they do have a slightly better track record when it comes to privacy than all of the others, and the fact that Firefox is open source means their promises can be verified. Given where Google makes its money, their commitment to privacy and security isn't in doubt, but it is slightly less believable. Apple and Microsoft are in a similar position to Google, just with the gates more firmly closed. In any case, if you're worried about your privacy, your browser is less of a problem than where you use it to go on the web, the things you download through it, and what services you sign into with it.

Firefox has long been touted as the best browser for privacy. 

It's open source, managed by the non-profit Mozilla Foundation (of which, it should be noted, Google is an investor), and is at the core of most privacy-focused browsers (like the previously mentioned Tor Browser Bundle). Even on the mobile side, Firefox for Android is open source and its code available to anyone who wants it. By most accounts, Mozilla is completely above board with what Firefox does, and the Foundation doesn't trade in user data, so there's no reason for them to harvest it.

Firefox does collect some information though. Firefox Sync uses your tab, password, bookmark, and other browser information to sync across devices, but that data is, like Chrome, encrypted. Firefox's privacy settings are easy to get to, and while they're not as granular as Chrome's, that's largely because there isn't as much to manage. All add-ons for Mozilla browsers are—unlike Chrome—reviewed before they're posted (although some are labeled "experimental" until they're tested.) This approach has helped them largely avoid the adware problem Chrome is suffering, although not completely. Some adware extensions for Firefox were identified, and others are just up front with what they do with your information.

Mozilla has a privacy policy for Firefox that explains what information is collected based on the features you use. it mostly involves sync, Personas, use of Mozilla Add-ons, crash and usage statistics, and so on. In most cases, unless you're part of Mozilla's Test Pilot or beta testing program, you're not sending much. Even the features that do send information, like Personas and Panorama, are so lightly used by most people that it's a non-issue. The message from Firefox's privacy policy is clear: All of the information sent is opt-in, not opt-out, and none of it is personally identifiable, although some of it may contain things like URLs you've visited, your IP address, and so on. The privacy policy also includes information about what Mozilla shares with third parties upon request. 

We reached out to the Mozilla Foundation for their input on this piece, but despite lead time, multiple follow-ups, and repeated requests, they declined to comment, and wouldn't even direct us to documents publicly available about their own commitment to privacy. Regardless, Mozilla has its own privacy woes as of late. Recently Mozilla announced that they are planning to introduce ads in Firefox in the form of "sponsored tiles." In short, the first time you open Firefox after a fresh install, the "speed dial" you see will be pre-populated with sites relevant to your location or sponsored by Mozilla. It's resulted in a bit of backlash. Some people have said the move will alienate new users by shoving ads in their face as soon as they install, and SiliconAngle said Mozilla "sold its soul." Mitchell Baker, Chair of the Mozilla Foundation, recently stepped up to defend the move on her blog. In any event, for a privacy-forward browser, it's a bold move.

Google obtains a great deal of information about you, but Chrome isn't a primary source of any of it. 

Gmail, your Google Search history, your YouTube account, your Google+ account, the files you store on Google Drive, and other browser-independent features are where your data really comes from, and in all of those cases, it doesn't matter what browser you use.

Google Ads Personalization keeps track of your interests, gender, and age:

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