This is a actually a bit of surprise. I always thought that Mobile Internet usage was more tilted in favor of Micro-blogging and email. However, recent Nielsen report suggests that the Mobile Internet usage by consumers mirrors the general use of Internet on whole. Search is still the most popular activity on Mobile Internet audience.
Personally for me, if I were to categorize, 90% of my use of mobile internet is for checking / replying emails, Twitter / FB and probably surfing some specific site. I have hardly searched net using my mobile phone.
Here are the findings by Nielsen:
Top 10 Mobile sites for December 2009
How do you use Internet on mobile?