U.S. mobile social media usage rose by 37 percent in the past year, with 72.2 million Americans accessing social networking sites or blogs via mobile device in August 2011, according to research by comScore, Inc.

Almost 40 million U.S. mobile users – over half of the estimated U.S. mobile social media audience – visit social media sites via mobile each day, reports the research firm.

comScore’s research also shows that, right now, more mobile users access social media sites via their mobile web browser than via a social networking app (42.3 million compared with 38.5 million).

This is likely to change, however. The growth in users accessing social media sites via social networking app is much higher than the growth in access via mobile browser. In the last year those accessing social media sites via mobile browser rose by 24 percent, compared with the huge 126 percent growth in the audience for social networking apps.

By 2013, social network advertising revenues will reach $10 billion worldwide, up from $5.54 billion this year, according to eMarketer. Facebook is set to grab the lion’s share of those revenues, with Facebook’s ad sales expected to climb from $3.8 billion this year to $7 billion in 2013 (70 percent of the total).

Twitter’s ad sales are expected to rise from $139.5 million in 2011 to $399.5 million in 2013. LinkedIn will also see impressive ad revenue gains. eMarketer expects LinkedIn’s ad sales to grow from $140.8 million this year to $249.6 million in 2013.

bigmouthmedia’s 2011 survey of U.K. affiliate marketers reveals that search engine optimization (SEO) and content marketing are the most popular Internet marketing tactics for generating traffic and sales. Affiliates are also embracing social media, with many using all three as well as other marketing tactics.

Here are the top 5 affiliate marketing trends noted by bigmouthmedia:

According to a recent survey of 1,745 business-to-business (B2B) Internet marketers, even the most effective B2B marketing tactics – such as website design, SEO and email marketing – were up to 50 percent LESS effective in 2011 compared with last year.

According to Marketing Sherpa, which conducted the survey, the upshot is that online marketers need to radically improve their game in order to meet the demands of B2B customers in the current economic environment.

Research In Motion’s (RIM’s) BlackBerry is doomed… and Apple’s iPhone will be relegated to runner-up… while Google’s Android operating system is set to become the market leading smartphone operating system. Well, that’s if eMarketer’s research is correct.

According to eMarketer, the end of 2011 will see the iPhone lose its market share leadership. At the same time, Android will end up installed on 37 percent of all smartphone handsets in the United States, a 13 percent increase since 2010.

More people are ‘Liking’ or sharing shopping items or links with their social media followers than forwarding them to friends via email, recent research shows.

A Responsys study of top online retailers finds that their use of ‘email-to-a-friend’ or ‘forward-to-a-friend’ via email has declined 15 percent since 2009, while the use of buttons and links enabling consumers to share with their social media network has increased by 12 percent.

When it comes to the most popular categories among daily deal website users, florists, malls, restaurants and day spas top the list, according to Scarborough Research.

According to Scarborough Research, local businesses most likely to benefit from targeting daily deal site users are restaurants, general retail stores, local specialty stores, health and fitness businesses, and automotive repair and servicing businesses.

Research from Slingshot SEO indicates that the top spot on the organic listings on Google gets 18.2 percent of all click-throughs, while the second spot gets 10.05 percent and the third position gets 7.22 percent.

Diverging from a recent study by Optify which indicates that the top spot yields 36.4 percent of clicks (http://www.kikabink.com/news/top-spot-on-google-gets-36-percent-of-clicks/) – Slingshot SEO’s ‘Mission ImposSERPble: Establishing Google Click-Through Rates’ research is based on a 6 month study.

One in five U.S. consumers (22 percent) are using digital media such as email, text messaging and Internet sites to get household coupons to help them save money on products and services.

Despite the popularity of online coupons, however, they aren’t the most popular source of savings coupons. Not yet, anyway. In fact, Scarborough Research finds that Sunday newspapers are the most popular source of household coupons, followed by retailers themselves and good old fashioned mail.

comScore, Inc’s 50 most popular U.S. websites for July 2011 shows Google sites accounting for the most traffic, followed by Yahoo!, Microsoft, Facebook and AOL.

In detail, the top 50 U.S. website properties, along with their monthly estimated unique visitors for July 2011 are as follows: