That’s the price that Facebook has set for each of the 421,233,615 shares it plans to sell as part of the company’s initial public offering today.

Normally, we would have teased the number in the intro, but after a rollercoaster four months of hype and speculation, we thought you had suffered through enough.

But what does this mean for Facebook and how big is this IPO really? And what other social media site made news on Wall Street this week?

That and more in this week’s news roundup.

1. Facebook Sets IPO at $38 a Share

The long wait is over.

In case you didn’t already do the math, at $38 per share, Facebook will raise $16 billion. This is the largest tech IPO in history and the third largest IPO ever, behind only Visa ($19.7 billion) and General Motors ($18.1 billion).

When it’s all said and done, Facebook’s value will be around $107 billion, and after selling 30.2 million of his own shares, Mark Zuckerberg will net $1.1 billion and still own 31% of the company. (That 31% is worth $19.1 billion, if you were interested.)

Bottom Line: This will be a huge payday for Facebook, but it comes with some big questions for the future of the company. The biggest question will be whether or not Facebook can solve the problem of monetizing social media and create a model that drives revenue through advertisements.

2. Most Recent Funding Brings Pinterest to $1.5 Billion Valuation

Not to be completely outdone by Facebook this week, Pinterest announced that the social network raised $100 million in funding from an investment group based in Japan. That brings Pinterest’s value to about $1.5 billion (up from just $200 million at the end of 2011).

Bottom Line: This most recently valuation says plenty about Pinterest – which has grown from 1 million users in May 2011 to 20 million users today – , and  and also shows us the value being put on social media startups

3. Local Social Advertising Expected to Reach $3.1 Billion by 2016

Annual local social advertising spending is expected to reach $3.1 billion by 2016, according to a new study from BIA/Kelsey.

That marks a 270% increase from the $840 million spent in 2011. Social alone is expected to account for around 8% of all online revenue by 2016, which is more than double its value in 2011.

Bottom Line: This significant spike is good news for small businesses that depend on local advertising and is sure to present more new and exciting social advertising opportunities.

4. Facebook Continues Mobile Push With New App

There’s been plenty of news about Facebook’s push into the mobile market over the last few weeks and this week was no different. The new Facebook Pages Manager app (which has only been released in Canada, New Zealand, and Australia at this point) allows administrators to manage their Pages on-the-go,  allowingthem to post updates, monitor analytics, and respond to comments from their mobile devices.

Bottom Line: It’s obvious that Facebook is not only working to provide a better mobile experience for their users but also for the small businesses and organizations that use the site to market their brands. New Zealand and Australia are usually the places where Facebook tests their new features and the fact that it is being released in Canada probably shows Pages should be available in the United Sites sooner than later.

5. Study Shows Weak Engagement on Google+

A new study of public data from 40,000 Google+ users has come up with some dismal findings about engagement on the social media site. The study found that the average post on Google+ has less than one +1, less than one reply, and less than one re-share. It also found that users had an average of 12 days between public posts and that 30% of users who make one post  never make a second.

Bottom Line: It’s important to note that the study only looked at public posts and therefore it may not tell the whole story for Google+. However, the research does show that Google+, which boasts more than 100 million active users, has some real problems when it comes to both engagement and retention.

Limited engagement means limited opportunities for business results. We’re still not entirely convinced of Google+ as a marketing tool either, so we’d say that this research indicates that it’s still best to sit on the sidelines.