This week in social media, Facebook introduced two new products in its continued quest for dominance in everything. Pinterest added "Guided Search" (a very Pinteresty search engine), Instagram's Explore page is now more personalized, and Facebook's $19 billion buddy, WhatsApp, reached half a billion users. It's time for Social Media Saturday!

Facebook 

Late in the week, Facebook unveiled the Facebook Audience Network (FAN), its very own mobile ad network that will let marketers develop both standard banner ads and customized ads for targeting specific users, based on Facebook's ever-expanding heap of everyone's personal information.

According to TechCrunch, the company has been testing mobile ad networks since 2012. After multiple tests and a couple reboots, FAN was born so that marketers could reach people based on Facebook's knowledge of their biographical and interest data and show them personalized ads. Mobile has already been a strong suit of Facebook, and it has been continuing its push for more ways of engaging users on mobile.

Meanwhile, Facebook introduced a product consistent with the second tier of its recent ambitions, which is social news. FB Newswire is a new platform introduced this week powered by News Corp.'s StoryFul. It helps journalists cut out the noise and find worthy news on social media by aggregating featured news and is one of the many ways Facebook is looking to tie itself ever closer to the news media.

WhatsApp

Finally in (technically) Facebook news, WhatsApp, the social messaging service Facebook CEO Mark Zuckerberg bought earlier this year for $19 billion, reached 500 million users this week.

On its blog announcement, WhatsApp attributed its recent growth to fast-growing markets in countries like Brazil, India, Mexico and Russia. As we previously mentioned when Facebook announced its acquisition, Zuckerberg sees the future in emerging markets, like Latin America, where the Internet and mobile technology markets are on the cusp of absolutely exploding, much like the U.S. was nearly a decade ago.

Pinterest

Pinterest this week began rolling out a new custom search engine for its mobile apps on iOS and Android called "Guided Search." When you enter a search term, Pinterest return with tiles with that tag, but it will also give you a list of related searches that are popular among users — also in a Pinteresty tiled format.

So if you're looking for "coffee makers," you might get options to add in "cold press" or "stove top" or "vacuum coffee maker." You can add those terms or move on to search them more in depth — all in the service of Pinterest's addictive browse-ability.

Instagram

Back to (technically) Facebook news (Wow, that network owns a lot of companies!), where Instagram has announced a more personalized Explore page in a very low-key way. Instagram co-founder Mike Krieger posted this on his Facebook page early this week:

Post by Mike Krieger.

Instagram replaced the "Popular" tab in 2012 with the "Explore" function, but it remained a place for widely-popular photos to accrue, as TechCrunch noted. Now it appears the company is looking for ways to help you discover more photos you like by displaying photos and videos liked by people you follow. This is making Instagram's network more personal in style and drawing it away from Vine, which is now known for making celebrities out of its globally-shared and retweeted content.

Also in Instagram news, Latin Post is on Instagram now! You can also follow us on Twitter, and Latin Post Tech is there, too!