Social media moves so fast, it's hard to keep up. Here are the week's top stories in scan-friendly format:

  • Google+ Gaining Ground: 10 Million Users Strong
  • StumbleUpon Releases iPad App
  • Apps Using Twitter Hits 1 Million
  • LinkedIn Overtakes MySpace to Become Number 2 Social Network

Google+ Gaining Ground: 10 Million Users Strong

Google+ is the search company's latest foray into social networking. After the disappointments of Google Wave (a project that was recently killed altogether) and Google Buzz, Google has an uphill battle in the social scene. It seems that Plus might have turned the tide according to one credible estimate of usage. According to Ancestry.com, Google has gained 10 million users nationwide as of this past Monday.

By using a surname analysis model, Paul Allen of Ancestry.com has tracked Google+ pattern of gaining users quickly. In a post on July 11, he estimates that 2.2 million users joined Google+ in the 32-34 hour period over the weekend. Have you seen people in your Twitter timeline and Facebook feed requesting and getting Google+ invites? Me too, and if the invite button stays up (Google has been taking it down to control intake of new users) the service could be an example of a rapidly growing social network.

If you've tried Google+, what are your thoughts? The sharp but minimalist design has been popular among users who are tired of Facebook's ads and relentless game invites. However, other Internet users say they don't have time in their day to devote to another social network.

StumbleUpon Releases iPad App

StumbleUpon is an innovative site that seeks to serve up sites you will find fascinating, but have yet to discover. StumbleUpon has been around for quite a while and has a happy and loyal user base of its website. The social web service is making the leap to mobile with an innovative iPad application released this week.

The StumbleUpon iPad app features a "social bar" that creates a section on each "stumbled" page that highlights a user who also liked a webpage. Also, if someone whom you follow liked the same page, their avatar will show up in the social bar. If not, a new person will pop up and the service will make a suggestion that you follow him or her. The new "social bar" helps make a human connection to the content you're surfing while on your tablet device. There are more features to the iPad app including a new "recommended for you" list and photo thumbnails of your interest.

If you're an StumbleUpon user who also has an iPad, check out the application. It might make your plain web browsing session more interesting and help you forge connections based on your interests.

Apps Using Twitter Hits 1 Million

We constantly track social networking services by a common metric: How many users are on the service. However, there's another measure of success that often gets left out and that is how robust the service is based on how many third-party applications help feed the platform. According to Twitter, the developer ecosystem is alive and well as the company recently announced that there are now more than one million applications that are registered with the Twitter service.

This means that, of all the applications on our iPads, phones and computers, more than one million tie in to Twitter to either get data from the service or allow you to "Tweet" a story. The one million mark means the ecosystem has grown rapidly in the last 12 months, as just one year ago, there were 150,000 registered applications. Adding to all this, Twitter claims to have a developer network made up of 750,000 developers around the world.

Making it possible for third-party applications to interact with Twitter is important to the company, as it means the platform becomes more robust and healthy with new content flowing in from a variety of sources. When's the last time you Tweeted a story from an app or external website such as CNN or News.com?

LinkedIn Overtakes MySpace to Become #2 Social Network

When you think of top social networks, which ones come to mind? Facebook and Twitter obviously, but what about Tumblr, LinkedIn or MySpace -- how do all these players rank? As of June 2011, Facebook was by far the most popular social network, but LinkedIn, the social net for professionals, has now nudged in the number two spot with an all-time high of 33.9 million unique visitors in June. MySpace fell to number three with 33.5 million unique visitors.

Following the top three, Twitter is the fourth-ranked social network as it jumped above the 30 million unique visitors. That's a nice growth pattern for Twitter, as just one month earlier in the month of May, there were 27 million unique visitors. Facebook is far in front of the pack with 157.2 million uniques. Additionally, Facebook recently announced that it's passed 750 million registered users, meaning this service is the big daddy of the social networking scene.

Which service is currently your favorite? Has a new social network gained more of your attention lately? Users typically are on more than one service, so it would be interesting to see what sites have gained your eyeballs in recent weeks/months.