After months of speculation, Facebook revealed its mobile advertising plans yesterday and, in a sign of how important mobile and social is becoming, the news came a mere day after Twitter announced a significant expansion of its advertising strategy for on-the-go users.

Facebook is making Sponsored Stories available in mobile for the first time while Twitter is making promoted tweets visible in its apps for iPhone and Android devices. The moves point to the importance of mobile and social, as well as the need to monetize mobile content.

?Facebook is making the brand experience on the go much richer,? said GianCarlo Pitocco, strategy director at marketing agency Mr Youth, New York. ?What is going to have to catch up is consumer behavior.

?For years, Twitter has been the mobile platform where consumers share while they have a dull moment,? he said. ?We are eager to see what shakes out after today as they continue to evolve mobile to be a richer and easier experience on the go.?

Mobile takes over
The big three social networks ? Facebook, Twitter and LinkedIn - are all moving into mobile advertising as the use of social networks via mobile devices continues to grow significantly.

However, of the three, Twitter is the only one that has always been mobile friendly.

?Twitter has a leg up over the others in mobile because it was built around using texting as the key engagement,? Mr. Pitocco said.

?People tend to use Twitter to communicate on the fly while Facebook is more about consumption and LinkedIn is not really about real-time engagement but about building relationships,? he said.

Social networks have a significant opportunity to attract marketing dollars via their mobile advertising strategies because they reach so many consumers on a regular basis throughout their day.

?We are at a turning point in terms of the platform,? Mr. Pitocco said. ?Mobile is taking over and you can see the decline of the PC industry before your eyes.

?Engagement on the fly is increasing and to be able to monetize those moments through Twitter, where people are so active, is a huge opportunity for them and could come to eclipse the revenue it generates on the desktop,? he said.

Twitters Promoted Tweets will appear in a user?s timeline similar to any other tweet. The focus will be on delivering content to users that is relevant to the conversation they are having via Twitter.

Previously, Promoted Trends and Promoted Tweets were available in search on Twitter?s mobile apps as well as on its mobile site. Additionally, Promoted Accounts and Promoted Tweets have been available on the mobile Web.

This is the first time Promoted Tweets will be made available in users? timeline in the Twitter?s mobile apps.

Promoted Accounts will also appear in users? lists of Who to Follow recommendations.

?With the fact that more than half of the active users on Twitter access the platform via mobile, this really opens up the opportunity to target the audience where they are actively using the platform and communicating and connecting with friends,? said Christian Borges, vice president of marketing at Mr Youth.

Relevancy is key
Brands will be able to be inserted into a conversation at a time when users are talking about a relevant topic.

For example, users who tweet during the Academy Awards show might see a Promoted Tweet from the Academy of Motion Picture Arts and Sciences or about a specific movie.

?It really allows us to insert relevant brands into a specific media moment,? Mr. Pitocco said. ?This allows us to reach a broader audience of consumers who actually care about what you have to say at that moment.

?We can get the brand to top of that conversation while they are participating in that conversation,? he said.

?It allows brands to jump in a hyper-relevant way.?

For Promoted Tweets in mobile to be successful, brands need to make sure they are providing relevant information.

?Brands have to make sure their promoted tweets are really relevant,? Mr. Pitocco said. ?What better platform than Twitter because it is so open and we can see what consumers care about and what they are talking about.?

Logical next step
For Facebook, marketers can now buy Sponsored Stories and the ad units will appear for the more than 425 million users who access the social network via a mobile device.

When a member visits a brand?s page on Facebook and clicks the ?like? button, the user?s network could see a message in their newsfeed saying that the member likes the brand.

Speculation that Facebook would soon introduce a mobile advertising solution has been widespread since the company?s filing for its initial public offering, in which it said that mobile use is growing. At the same time, the social network said that it needs to be able to monetize mobile in order to continuing growing its advertising revenue.

?With the rise of smartphones and the ability to access information and the ability to connect with brands and consumers on the go, it only makes sense that this was the next step,? Mr. Borges said.

Final Take
Chantal Tode is associate editor on Mobile Marketer, New York