A number of people have asked about the relationship between Google Chrome, Chromium, and Google, specifically in regards to what data is sent to Google or other providers. This is meant to provide a complete answer to that question, and as you will see below, almost all such communication can be disabled within the options of the product itself. Before getting too deep into the question though, it is helpful to have a common set of terminology. Chromium is the name we have given to the open source project and the browser source code that we released and maintain at www.chromium.org. One can compile this source code to get a fully working browser. Google takes this source code, and adds on the Google name and logo, an auto-updater system called GoogleUpdate, and RLZ (described later in this post), and calls this Google Chrome. As such, everything which applies to Chromium below also applies to Google Chrome, while there are some things that apply to Google Chrome (such as the auto-updater) that do not apply to Chromium.

Communications between Chromium (and Google Chrome) and service providers

Search Suggest: If you type a few letters into the address bar and pause, Google Chrome will send the letters you have typed to your default search provider so it can return a list of suggestions. These suggestions will appear in the drop-down that appears below the address bar.  The letters you have typed are only sent if your search provider provides a suggest service. As an example, suppose your search provider is Google and you're located in the United States. If you type "presid" and pause, you might get suggestions like "Search Google for Presidential Polls", "Search Google for Presidents", as well as a suggested website (a page listing the Presidents of the United States on www.whitehouse.gov). Your provider for search suggestions may log these suggest queries. In the case of Google, we log 2% of these suggest queries, and anonymize these logs within approximately 24 hours as described in an earlier blog post.

If you choose to accept a search query suggestion, that query will be sent back to your search provider to return a results page. If you choose to accept a suggested website, the accepted suggestion is not sent back to your search provider unless you've opted-in to stats collection. If you have, Google may collect the suggestion you accepted along with the letters you had typed so far in order to improve the suggest service. If you are in a different part of the world, or are using a different search provider, you may get different suggestions. 

If you do not wish this data to be sent to your search provider, you have a number of options. The first is to use incognito mode, in which the suggest feature is automatically disabled. You may still get suggestions from your local history stored on your computer, but no suggest queries are sent to your search provider. You can also turn off search suggestions permanently. Finally, you can change your search provider. If your new search provider supports suggest functionality (such as Yahoo!), suggest queries will be sent to this new provider. If it does not support suggest functionality then suggest queries will not be sent.

Safe Browsing: Safe Browsing is a feature designed to help protect users from phishing and malware. The way Safe Browsing works is that roughly every half hour, an updated list of suspected phishing and malware websites is downloaded from Google and stored locally on your computer. As you browse the web, URLs are checked against these lists that are maintained locally on your computer. If a match against the list is found, a request to Google is sent for more information. This request is formed by taking a 256-bit hash of the URL, and sending the first 32-bits of that hash. To be clear, requests are not sent for each page you visit, and we never send a URL in plain text to Google.  More information on how this feature works is available in the Google Chrome help center. This feature can also be disabled, although disabling this feature means that you will not be warned before you visit a suspected phishing website, or a website suspected of downloading and installing malware onto your computer.

Suggestions for Navigation Errors: By default, Chromium (and Google Chrome) offer smarter error messages when you encounter unavailable websites. These error messages automatically generate suggestions for webpages with web addresses similar to the one you're trying to access. This feature involves sending the URL that failed to Google, to obtain suggested alternatives. This feature can be disabled in the options dialog.

Which Google Domain: Shortly after startup, Chromium (and Google Chrome) send a request to Google to determine which localized version of Google to use, e.g. whether to direct queries to google.com, google.de, google.co.uk, or another localized version of Google. This is important because sending queries to the right localized Google domain ensures that you get results that are more relevant. For instance, a user searching for "Football" on google.co.uk would get results for European football ("soccer"), while a search on google.com might favor results on American football. Currently (in Google Chrome version 0.2.149), this request is sent regardless of what your default search engine is set to. This was an oversight, and this information was never used to track users.  In Google Chrome 0.3, this request will only be sent if your default search provider is set to Google. This change has already been made in the Chromium source code. 

Communications between Google Chrome (but not Chromium) and service providers

Usage Statistics and Crash Reports: This option is opt-in, and is disabled by default. Users can elect to send Google their usage statistics and crash reports. This includes statistics on how often Google Chrome features, such as accepting a suggested query or URL in the address bar, are used. Google Chrome doesn't send other personal information, such as name, email address, or Google account information. This option can be enabled or disabled at any time.

GoogleUpdate: When you install Google Chrome, GoogleUpdate is also installed. GoogleUpdate makes sure that your copy of Google Chrome is kept up to date, so that when updates are released your version is automatically updated without any action required on your part. This is especially important to make sure that users are protected by the latest security fixes that Google releases. As part of these update checks, two unique, randomly generated IDs are sent, along with information such as version number, language, operating system, and other install or update-related details. This information helps us accurately count total users, and is not associated with you or your Google Account. More information is available in the Google Chrome help center. GoogleUpdate cannot be disabled from within Google Chrome. GoogleUpdate is automatically uninstalled on the next update check (typically every few hours) after the last Google product using it is uninstalled. The GoogleUpdate team is working on functionality to allow GoogleUpdate to be uninstalled immediately after the last app using it is uninstalled.

RLZ: When you do a Google search from the Google Chrome address bar, an "RLZ parameter" is included in the URL. It is also sent separately on days when Google Chrome has been used or when certain significant events occur such as a successful installation of Google Chrome. RLZ contains some encoded information, such as where you downloaded Google Chrome and where you got it from. This parameter does not uniquely identify you, nor is it used to target advertising. This information is used to understand the effectiveness of different distribution mechanisms, such as downloads directly from Google vs. other distribution channels. More information is available in the Google Chrome help center. This cannot be disabled so long as your search provider is Google. If your default search provider is not Google, then searches performed using the address bar will go to your default search provider, and will not include this RLZ parameter.

Updates to Google Chrome's privacy policy
In addition to explaining what communications take place between Google Chrome and service providers, we want to let you know that we are updating the Google Chrome privacy policy to reflect a change that we have made to the browser to protect user privacy.

Since the release of Google Chrome, we have modified the way its browsing history works so that the searchable index of pages you visit does not include sites with "https" web addresses. However, thumbnail-sized screenshots of these pages will be captured for local use, such as on the new tab page. The updated version of the privacy policy reflects this change. As before, your browsing history stays on your own computer for your convenience and is not sent back to Google. And remember: You can delete all or part of your browsing history at any time, or you can conduct your browsing in incognito mode, which does not store browsing history. 

We hope this new language makes it more clear how Google Chrome works. For more information, check out the Google Chrome privacy video on our YouTube Google Privacy Channel