The most popular Google services by usage by Alexa

According to Alexa Google is the most popular site in the world while number 2 is Facebook.

And the most popular Google services aka sub sites by usage (hours spent on the site) are:

 

Percent of all Google site visitors

1. Search google.com  71.36%
2. Gmail mail.google.com 44.93%
3. Profile accounts.google.com 36.34%
4. Google Drive (Google Docs) docs.google.com 9.12%
5. Google Plus plus.google.com 7.72%
6. Google Translate translate.google.com 6.07%
7. Help support.google.com 5.00%
8. Maps maps.google.com 4.91%
9. Google Drive drive.google.com 4.10%
10. Play play.google.com 2.59%
11. Adwords adwords.google.com 2.18%
12. News news.google.com 1.75%
13. Sites sites.google.com 1.01%
14. Code code.google.com 0.91%
15. Feedburner feedburner.google.com 0.78%
16. Product forum productforums.google.com 0.74%
17. Groups groups.google.com 0.67%
18. Url url.google.com 0.56%
19. Developers developers.google.com 0.56%
20. Picasa picasaweb.google.com 0.55%
21. Image search images.google.com 0.53%
22. Ejabat ejabat.google.com 0.46%
23. Google Scholar scholar.google.com 0.14%

Interesting isn't it? So Google documents are used more than Google Plus while Picasa for storing and viewing photos is not used that much. By the way, for a researcher the Google Scholar is quite useful service. :)