As the two newest social networks, Google+ and Pinterest have gotten a lot of attention recently. It's no surprise. Each has experienced rapid growth and adoption, leaving marketers wondering how to effectively leverage each new platform for business. So which -- if either -- are worth a marketer's time? And how do you decide?

To make the decision a little bit easier, we've compiled a new ebook, Battle of the New Social Networks, which gives you a side-by-side comparison of the pros and cons of Pinterest and Google+. The ebook is available for free download -- no form completion required -- here.

So exactly how impressive is the growth of Google+ and Pinterest comparatively? We also pulled together 35 interesting facts about the two social networks to give you a better sense of how the two networks are faring. Check 'em out!

Google+ Statistics

1) As of April 2012, Google reports that Google+ now has 170 million active users. (Google) Tweet This Stat

2) Google+ attracted 20 million users within the first 3 weeks of its launch. (comScore) Tweet This Stat

3) As of January 2012, American users spent an average of 3.3 minutes on Google+. (eMarketer) Tweet This Stat

4) As of January 2012, Google+ accounted for .22% of referral traffic, falling from .24%. (Shareaholic) Tweet This Stat

5) Websites using the +1 button generate 3.5x the Google+ visits than sites without the button. (HubSpot) Tweet This Stat

6) Two of the biggest user groups on Google+ are college students and software developers. (Remcolandia) Tweet This Stat

7) 63% of Google+ users are male. (Remcolandia) Tweet This Stat

8) Over 40% of marketers report that Google+ is "useful to critical" for their business. (HubSpot 2012 State of Inbound Marketing Report) Tweet This Stat

9) Google+ is expected to attract 400 million users by the end of 2012. (Remcolandia) Tweet This Stat

Pinterest Statistics

10) Pinterest is now the 3rd most popular social network in the U.S. in terms of traffic. (Experian) Tweet This Stat

11) As of February 2012, Pinterest had accumulated 10.4 million users. (AppData) Tweet This Stat

12) Over 80% of pins are repins. (RJMetrics) Tweet This Stat

13) Pinterest is retaining and engaging users as much as 2-3 times as efficiently as Twitter was at a similar time in their history. (RJMetrics) Tweet This Stat

14) Daily Pinterest users have increased by more than 145% since the beginning of 2012. (Mashable) Tweet This Stat

15) As of January 2012, American users spent an average of 97.8 minutes on Pinterest. (eMarketer) Tweet This Stat

16) Over 1/5 of Facebook-connected users are on Pinterest daily (which represents more than 2 million members). (AppData) Tweet This Stat

17) 80% of Pinterest's users are female. (comScore) Tweet This Stat

18) Estimated unique visitors to Pinterest.com increased by 429 percent from September to December 2011. (Compete) Tweet This Stat

19) The quality of the average new Pinterest user (as defined by their level of engagement and likelihood to remain active) is high but declining. Users who have joined in recent months are 2-3 times less active during their first month than the users that came before them. (RJMetrics) Tweet This Stat

20) 30% of Pinterest users are women 25-34 years old. (Ignite) Tweet This Stat

21) Pinterest users in the U.S. are more likely to live in midwestern states than your typical social networker. (comScore) Tweet This Stat

22) The top interests on Pinterest in the U.S. include crafts, gifts, hobbies/leisure, interior design, and fashion designers/collections. (Ragan.com) Tweet This Stat

23) Etsy is the top site in terms of “source domains.” (Source domains are the sites that content on Pinterest links to externally.) Google is second, followed by Flickr, Tumblr, and WeHeartit.com (RJMetrics) Tweet This Stat

24) As of January 2012, Pinterest accounted for 3.6% of referral traffic. (Shareaholic) Tweet This Stat

25) Total same-store referral traffic from Pinterest to five specialty apparel retailers rose 389% from July to December 2011. (Monetate) Tweet This Stat

26) In January 2012, Pinterest reached 11,716,000 total unique visitors. (comScore) Tweet This Stat

27) With over 11 million unique monthly visitors (and counting), Pinterest became the fastest standalone website to eclipse the 10 million per month mark ever. (PR Daily) Tweet This Stat

28) A call-to-action pin description sees an 80% increase in engagement. (Pinerly Study) Tweet This Stat

29) Tutorial & guide/DIY & recipe pins see a 42% higher click-through rate than other pin types. (Pinerly Study) Tweet This Stat

30) Pins related to trending topics see an average of 94% increase in click-throughs. (Pinerly Study) Tweet This Stat

31) The best time to pin during the day is between 2 and 4 PM EST. (Pinerly Study) Tweet This Stat

32) The best time to pin in the evening is between 8 PM and 1 AM EST. (Pinerly Study) Tweet This Stat

33) Shoppers referred by Pinterest are 10% more likely to make a purchase than visitors who arrive from other social networks, including Facebook and Twitter. They’ll also spend 10% more on average. (Wayfair) Tweet This Stat

34) Pinterest referrals spend 70% more than visitors referred from non-social channels, including search, according to industry reports. (Wayfair) Tweet This Stat

35) In the month of March 2012, HubSpot's visitor-to-lead conversion rate for Pinterest was 15%, compared to just 9% from Google+. (HubSpot) Tweet This Stat

How have you been using each social network? What insights can you share for other businesses considering the two for marketing?