From Google’s antitrust hearings to updates to its social platform, Google+, the search giant dominated news headlines this week, yet Facebook’s announcements make clear that Mark Zuckerberg’s social network is still the leader in the social (and social marketing) space.

Social media marketing, overall, proves its worth in a Unity Marketing study released this week. The study reveals that 65 percent of affluent shoppers say social has impacted their purchase decisions. Nearly half say social media information inspired them to visit a website and/or make a purchases. Facebook in particular is an important channel for small businesses trying to convert online audiences across income demographics. Forty-eight percent of SMB marketers say their Facebook campaigns have led to conversions.

Further demonstrating its relevancy to consumers – and marketers – Facebook reminded Americans of the updates it has launched in recent weeks. These include Subscribe functions that allow users to manage the content they see, Friends Lists that enable them to share content with select groups of users, designation of Top and Recent content in the News feed and a Ticker update that lets users engage friends and brands according to News Feed activity without navigating away from the pages they are on. Notably, all of these updates place a premium on the relevancy of content specific users, and marketers should plan social content marketing campaigns accordingly.

The video documenting all of Facebook’s previous updates served as recap leading into a major update. On Thursday, the company announced at F8 that it is completely revamping users’ profiles with a new Timeline format. The company also announced that it has hit the 800 million-user mark, solidifying that it offers unparalleled marketing reach.

Of course, Google+ may soon be boasting higher user numbers. The search giant opened its social network to everyone this week, which could help the company gain more users and more engagement (Brafton reported that the amount of Google+ posts had dropped considerably in August).

The company also announced new Hangouts updates that businesses hoping to connect with consumers might like. For instance, users can now share screens and “doodle” on shared docs while in Hangouts sessions, positioning the feature as a viable conferencing platform. Also, the company announced Google+ search. As Brafton reported, the feature pulls from People, content shared on Google+ and web content culled by Sparks to offer relevant results within the social network. Content can be displayed according to recency (necessitating frequent website updates) or popularity among Google+ users’ friends (necessitating social sharing).

In other Google search news, at this week’s Online News Association conference, Local SEO Guide, NewsKnife and Perfect Market shared insights from a study on Google News ranking signals. They found that developing niche authority via focused and targeted content, using keywords in headlines and garnering social shares for news articles are three of the top ranking factors for Google News. These factors were even more important than breaking a story, according to the top publishers they surveyed. This info should be valuable to marketers as Google News is a valuable, less-cluttered search space where they can reach convertible audiences.

Google is by far the leading search engine – and perhaps on its way to becoming a top social player. For marketers, this means website marketing must consider the company, but for the U.S. Sentate, this means potential trouble. Google had a Senate hearing this week where it had to defend itself against the idea that it is monopolistic. Search Engine Land’s Danny Sullivan was live-blogging the event. 

On a lighter note, Google announced updates to Instant Previews, giving users a larger image of the pages returned for queries.

Bing is also changing its SERPs. As Brafton reported, Microsoft’s search engine now includes action buttons alongside results based on the activities most common to a website. The feature is available for businesses in seven key verticals, and marketers may find it places valuable CTAs directly alongside their organic search listings.

Bing, Google and Yahoo all came out on top as the web’s most visited properties for August. The search sites beat out Facebook, which ranked fourth, according to comScore’s latest report. However, mobile web visits might be a different story…

As Brafton reported, social apps are some of the most popular mobile applications. The rising use of social apps correlates with growth in mobile device purchases and subsequent on-the-go web access. In fact, tablet shipments will exceed 55 million by the year’s end, and mobile marketing budgets have hit $56 billion. Search and social marketers catering to these audiences should consider the value of optimizing content for local and industry-specific shoppers. As Brafton reported, keyword variety for mobile SEO is key to success and smartphone searchers tend to look for businesses according to category. These tips will come especially handy as the holiday shopping season rolls around; Google anticipates that 44 percent of last-minute shoppers will rely on their mobile devices to make purchase decisions.

Combining search, social and mobile campaigns is part of the growing need to integrate overall marketing campaigns. One business saw conversions were nine times more frequent among prospects it called who had also received an engaging email newsletter as opposed to those who hadn’t received the marketing messages. (On a related note, marketers should aim for short, brief email marketing messages, which had higher CTRs than longer messages.)

Next week, marketers will want to look out for figures on Google+ engagement in light of the platform’s new features and open access. Also, watch out for reactions to Facebook’s update to determine which platform is holding consumers’ interests (and which platform merits marketing investment). Stay tuned!