Google Chrome uses WebKit to render web pages--the same rendering engine as Apple's Safari. WebKit is the most widely used rendering engine, as it is used by Chrome/Chromium, Safari, iOS's Safari, Android's browsers, and others.
Chrome is extensible, like most (all?) modern browsers. Extensions can be found anywhere, but one central place to find them is the Chrome Web Store. Note: installing extensions from sites other than the Chrome Web Store can be dangerous.
Some popular extensions and a few that I use:
Adblock: Blocks ads, including in youtube videos.
Google Dictionary: highlight a word on the web, a definition pops up.
HoverZoom: Hover your mouse over a thumbnail image, see the full image in a popup. Works on most, but not all, sites.
Evernote Web Clipper: From the context menu, you can add things to an Evernote notebook. Also enables searching of your Evernote notes when you search Google (or other search engines)
Also available from the Chrome Web Store are games, themes and full screen apps.
Tips & Tricks:
You can "pin" tabs in the tab bar. To do this, right click on a tab and hit "Pin Tab". This shrinks the tab down to just the favicon, and saves a ton of room on the tab bar. Firefox calls this feature "App Tabs".
You can have multiple "Users" of a single Chrome install. You can enable another user by going to Wrench menu -> Settings and clicking on "Personal Stuff". From there, click "Add new user". After you have another user, you can pick your own icon and set names for each user. The icon is displayed in the title bar, so you can see at a glance which profile you're using. With a new user, you can have a completely different Chrome experience. Different google account, different saved passwords, different bookmarks, history, extensions, themes, etc. From the icon displayed in the title bar, you can switch users (actually launch a new browser window as the newly selected user). Note: this is not the same as creating a new "profile", which you have to do manually. Any user can access any other users data--it's more for convenience than security! Here's a video Google created showing you how.
After performing a manual search on a site once, Chrome's Omnibox will give you the option to search directly by pressing Tab. For instance, I have searched on IMDB.com before. Therefore, when I type "imd" in the Omnibox, I can press the Tab key and then enter a string to be searched on imbd.com. Hitting enter will then take me straight to the imdb results page. As far as I know, this works with any page where a search is performed. At the very least, it works on most. You can also manually add search engines through Chrome's settings, but performing a simple search on the site is much easier.
Going along with the last tip, Ctrl+L will instantly focus on the Omnibox. Ctrl+K focuses the Ominbox with a "?" denoting a default search will be performed based on the string entered. However, the ? is not really necessary, as Chrome will automatically search when text other than a URL is entered. It's useful if you're trying to search for a URL (rather than going to it). I believe these shortcuts are defaults across web browsers--at least I know Firefox uses them.
You can make "Application Shortcuts" out of just about anything. While you're on a page you want to make a shortcut to, go to the Wrench Menu -> Tools -> Create Application Shortcuts... You can then add a desktop/start menu shortcut that will instantly launch that particular site again. It's especially useful on a site like gmail--the "application shortcut" will open a new Chrome window when clicked that doesn't have navigation options. Basically you can open a site as a sort of "native app".
If you go to the URL about:flags (or chrome://flags, which about:flags redirects you to), you can find a slew of experimental options. Warning: these are potentially unstable!
In chrome://history (or by hitting Ctrl+H), you can see all your browser history, and even search within it! You can also clear all or part of your history from this screen.
chrome://downloads (or Ctrl+J) opens a similar screen for your downloads.
Several Google Chrome features use your personal information, such as the webpages you're visiting, to enhance and protect your experience on the Web. Learn what information is being used and how.
- Suggestions for navigation errors
In cases where the web address does not resolve or a connection cannot be made, Google Chrome can show suggestions for the page you were trying to reach. The browser sends Google the URL of the page you're trying to reach in order to offer you suggestions of alternative or similar webpages. Learn more about navigation error suggestions
- Predictions in the address bar
The browser can use a prediction service to show you related queries, matches from your browsing history, and popular websites as you type in the address bar. If your default search engine uses Google's prediction service, Google Chrome sends the text you type in the address bar to Google in order to retrieve suggested searches and sites, which are then displayed in the address bar menu. Google only records a random two percent of this information received from all users and the information is anonymized within 24 hours. Learn more about the address bar prediction service
- Predictions for network actions
When you visit a webpage, Google Chrome can look up the IP addresses of all links on the webpage. Browsers use the IP address to load a webpage, so by looking up this information in advance, any links you click on the webpage will load faster. Websites can also use pre-rendering technology to pre-load the links that you might click next.
- Phishing and malware protection
Get an instant alert whenever Google Chrome detects that the website you're going to may be harmful. The browser sends a partial copy of the URL you're visiting to Google to check it against a list of known phishing and malware sites. Learn more about phishing and malware detection
- Usage statistics and crash reports
Help us prioritize the features and improvements we should work on. Permit the browser to send Google information about your installation of the browser and information from files, applications, and services that are running whenever you experience a browser crash. Google Chrome doesn't send other personal information, such as name, email address, or Google Account information. Learn more about usage statistics and crash reports
- Cookie settings
Cookies are files created by websites you've visited to store browsing information, such as your preferences for the website or profile information. By default, Google Chrome saves all cookies onto your computer, but you can restrict how it handles different types of cookies. Learn more about cookie settings
- Suggestions for spelling errors
You can choose this option to enable a smarter spell-checking function by sending the text you type into the browser to Google's servers. This allows Chrome to use the same spell-checking technology as Google search. To enable this feature, right-click a misspelled word and select Ask Google for Suggestion.
In addition to changing the above, you can install the SRWare Iron browser, which is built from Chromium and does not have the tracking options at all, as well as a few other features. Check out the differences here. (thanks to frapper)
If you want to search Google while still enabling features that are normally enabled (history, personal results, whatever else), you can log out of your Google account first and then search. However, this is a cumbersome way to do it. Instead, you can launch a new Private Browsing Window (Ctrl+Shift+N by default) and perform your search that way. You aren't logged into your Google account in a private session, and so nothing will be saved. You can then close the private window and still be signed into Google.
What are some of your favorite extensions or tips?