Among the many things your Mac is tasked to do is to help you stay in touch with other people. And the first step in doing so is to have some notion of how to contact themthrough email, snail mail, phone, chat, FaceTime, and social networking services. The repository for this vital information is Mountain Lion's Contacts application. Formerly known as Address Book, Contacts is often overlooked, since many people think that the job it handles is mundane. But Contacts has hidden depths, including the ability to pull in Twitter handles and Facebook friends automatically, sync Google contacts, display a map of a contacts address, and help you put faces to names.

Get rid of the leather look

Those who feel that a computers address book need not be slathered with the look of a real-world address book may find Contacts leather theme tiresome. Thankfully, you can dump that themeand best of all, no Terminal is required. Just use Fredrik Wikers donationware Mountain Tweaks utility.

Launch Mountain Tweaks, select the Mountain Lion Tweaks tab, and click the Yes button that appears next to the 'Remove Leather from Contacts (ML)' item. An installer application will launch and walk you through the steps for removing the old look and applying a cleaner theme. When you next launch the Contacts application, it will sport a steely-gray theme. If later you long for the classic look, launch Mountain Tweaks again and click No next to the Contacts options; the tool's installer will revert the theme to its original look.

You can use Mountain Lion Tweaks to do the same for the Calendar app too, if you'd like a matching set. Just click the Yes button that appears next to the 'Remove Leather from Calendar (ML)' item.

Automatically connect Twitter accounts to contacts

If youre on Twitter, many of your friends probably are as well. Heres an easy way to add Twitter handles to your contacts when running Mountain Lion. Launch System Preferences, select Mail, Contacts & Calendars, and, if you havent done so already, click the plus (+) button and select Twitter. In the sheet that appears, add your Twitter account by entering your username and password and then clicking Sign In.

With your Twitter account established, select it and then click the Update Contacts button. A dialog box appears, asking whether to update your contacts with their Twitter handles. Click Update Contacts.

OS X searches your contacts for any phone number or email addresses that match Twitters user database. In a short time, the job is complete.

Open Contacts and select a likely contact, and youll see a Twitter entry followed by the handle that contact uses with the service. If you now click the word Twitter, youll see Tweet and View Tweets options. Choose Tweet, and you can direct a tweet at the contact; if you choose View Tweets, the Twitter application opens and shows you that user's Twitter stream.

Note that Twitters ability to link contact information and Twitter handles isnt always everything it could be. For instance, if one of your contacts has more than one account associated with their email address or phone number (or if someone else in that contacts home or business uses the same address or phone number), Twitter may associate the wrong handle with that contact. Before tweeting blindly to someone based on Twitters best guess, double-check the handle. If you don't have the right one, edit that contacts Twitter field to use the identity you prefer.

Add Facebook info to contacts

Under Mountain Lion you can also add Facebook friends to contacts. To do so, go to System Preferences > Mail, Contacts & Calendars and click the Facebook entry. Youll be prompted for your Facebook username and password. After you enter that information and sign in,  your Facebook friends are added to Contacts. A Facebook group will appear in Contacts, and any member of that group will have a Facebook entry within their contact card. Click the Get Profile Photos button at the bottom of the Facebook entry window to add your friends' chosen images to your contacts with identified Facebook accounts.

Sync Google contacts

If you have an uneven collection of email addresses and phone numbers scattered between OS X Contacts and Google Contacts, help is in sight. Google recently made it possible for users to sync contacts using the CardDAV protocol, which means you can now easily sync contacts between Google and your Mac. You have a couple of ways to do that.

The first is to open System Preferences, select Mail, Contacts & Calendars, and then click Add Other Account (scroll down to the bottom of the list that starts with iCloud). In the sheet that appears, select Add a CardDAV account, and click Create. In the resulting 'Add a CardDAV Account' sheet, enter your Gmail username and password; in the Server Address field enter, and click Create. A Google WebDAV account will be created, and youll have access to your Google contacts within the Contacts application.

You can also do this from within Contacts. Choose Contacts > Preferences, and then click the Accounts preference. Click the plus (+) button at the bottom of the window. In the sheet that appears, confirm that CardDAV is selected in the Account Type pop-up menu. Add your Gmail username and password in the appropriate fields, and enter in the Server Address Field. Click Create, and your Google contacts will sync.

Click contact headings and see what happens

When you're viewing a contacts card in Contacts, one of the best ways to discover the app's new features is to try clicking the card's headings. For example, if you click the Facebook heading, you can view the contacts profile or see the photos theyve posted on Facebook.

Click an address heading, and you'll see a 'Map this Address' option that uses Google maps within your Web browser. Your other options here are Copy Mailing Label (which creates a formatted copy of the address perfect for insertion into a mailing-label template) and Copy Map URL (which sends it to the clipboardthis is the option youd choose if you wanted to email or text that location to someone).

You'll find some thoughtful touches hidden in the headers. Need to make a call from across the room? Click a phone heading and choose Show in Large Type. The phone number will appear on your display in type big enough to be readable from a distance.

Add images to contacts

One of Contacts most overlooked features is the ability to add images to your contacts. This function is helpful when you need to remind yourself what the VP of Very Important Things looks like before you enter a room full of similar stuffed shirts.

The easiest way to accomplish this is to drag an image file on top of a contacts Image field. (You can do so via the Finder, or drag iPhoto or Aperture images directly from your photo library to this field.) If you dont have an appropriate image, you can add a generic one: First, double-click the Image field to produce a window that, in Mountain Lion, includes Defaults, Recents, and Camera (if your Mac has a camera). Choose Defaults, and youll see the standard collection of OS X imagesparrot, penguin, piano keyboard, basketball, and so on. Select Recents, and youll see images youve recently assigned to other contactshelpful if youve assigned a clown icon to your boss and want to dish out the same treatment to the woman who runs the accounting department. If you click Camera, your Macs camera becomes active so that you can take a picture and use that photo as an icon.

Regardless of how you assign an icon, you then have the ability to edit it. If you wish, resize it using the Size slider, and click the Effects button to add Apples PhotoBooth effects to your images. When youve edited an image to your satisfaction, click it and then click the Done button.

On occasion, icons will appear to update themselves. For example, if youve added a Facebook account within the Mail, Contacts & Calendars preference and chosen to include your friends profile images, those images will change when your friends update them.

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