With roughly half of all U.S. mobile subscribers using smartphones, Facebook is very focused on serving ads to mobile users. This is obvious when you see Facebook's revenue was up in Q3 because of mobile advertising.

"There are over 12 million small businesses using Facebook, and if you do the basics of updating your page, it is a low-cost, rich visual presence in mobile without needing a mobile website," says Matt Idema, the director of monetization product marketing for Facebook, who focuses on small businesses and their use of Facebook pages. Idema advises all businesses to fill out their profile with location, phone, and hours of operation as well as an attractive cover photo. Getting past the basic profile, there are four, straightforward ways to reach customers on mobile.

1. Promoted Posts

Using Promoted Posts, you, a page owner, can take a post you've already created and pay to ensure it is seen by existing fans as well as friends of fans. Idema adds, "You can target page posts according to gender, age, geography, and other factors, and should promote the post so that as many people as possible will see it." An example might be a picture of a sale item or a picture of food you have posted on your Facebook page that you then promote. There's no distinction between desktop and mobile in Promoted Posts--your fans see the post on whatever device they're using at the time.

2. Facebook Offers

Another simple marketing unit is Facebook Offers, which allows couponing, discounts, and deals. Offers can be redeemed in-store, online, or have an option for both. Customers can print an offer or show it to an employee via a mobile phone, or the offer can be redeemed on a website via a code. Micah Gaudio, mobile social strategist of Via Digital Media, has successfully used offers for his client SweetFrog Frozen Yogurt. "We average a 2.9% redemption rate on Facebook Offers, and we've had some stores report over 10,000 in-person redemptions." Facebook provides several case studies of businesses that successfully use offers. Promoting offers can increase your reach. A page owner can limit the number of offers shared per day, or make the number unlimited.

Once a fan claims the offer, it is shown to their friends in their news feed, providing a viral bump in exposure. Gaudio has used offers to bring fans to a custom tab on the Facebook page where they are encouraged to share their mobile number for a chance to win a free yogurt. These users convert at an even higher percentage once acquired in this way.

3. Facebook Ads

"The majority of small businesses use the self-service Web interface for ads," says Idema. Facebook has made it easier to run ads in the main news feed, which gets them running on mobile as well. You can use ads to acquire "Likes" for a page, or to promote content, which is very similar to promoting a post. Ads have numerous targeting options, letting page owners reach a specific audience segment.

For those more technical users, Facebook offers a Power Editor to do really fine-grained targeting for mobile users. "If you want to target mobile users directly, you should download it, dive in, learn how to use it," says Jason Keath, CEO of social media marketing and training company SocialFresh. "The Power Editor lets you target local Zip codes, phone models, and more. Consider targeting people who haven't yet liked your page to get them to do so, then reach them via Promoted Posts or offers--this can be cost effective." Keath also offered a serious power tip. If your company has an existing email list, you can upload that list to Facebook via Power Editor, and it will target your existing email subscribers with ads.

4. Sponsored Stories

Sponsored Stories is another type of ad unit, in which a user's interaction with a page (liking it, commenting on a post, checking in) becomes a promoted item in their friend's news feeds. "By selecting Sponsored Stories, small businesses will get news-feed ads on desktop and mobile." One targeting option is for people who have used Facebook on mobile, which doesn't guarantee they'll see your ad on mobile, but helps limit your audience to those who are mobile users.

Reaching customers via mobile has become much easier in recent months, and most businesses can do so without diving into advanced features or power settings.

Let us know if you've had success with these techniques and others in the comments below.