Microblogging is a broadcast medium in the form of blogging. A microblog differs from a traditional blog in that its content is typically much smaller, in both actual size and aggregate file size. Microblogs “allow users to exchange small elements of content such as short sentences, individual images, or video links”.
As with traditional blogging, microbloggers post about topics ranging from the simple, such as "what I'm doing right now," to the thematic(主题的), such as "sports cars.” Commercial microblogs also exist, to promote (促进) websites, services and/or products, and to promote collaboration within an organization.
Some microblogging services offer features such as privacy settings, which allow users to control who can read their microblogs, or other ways of publishing rights besides entering the web-based interface.(界面) These may include text messaging, E-mail, or digital audio.
The first microblogs were known as tumblelogs. The term was invented in a blog post on April 12, 2005. However, by 2006 and 2007, the term microblog came into greater usage for such services provided by Tumbler and Twitter. Other leading social networking websites Facebook, MySpace, LinkedIn, and XING also have their own microblogging features, better known as status updates.
Several studies, especially by Harvard Business School have tried to analyze the usage behavior of Microblogging services. Many of these studies show that for services such as Twitter, there is a small group of active users contributing to most of the activity.
Twitter, Facebook and other microblogging services are also becoming a platform for marketing and public relations, with a sharp growth in the number of social media marketers. The Sysomos study shows that this specific group of marketers on Twitter is much more active than general user population, with 15% following more than 2,000 people.
Why is a microblog different from a traditional blog?

A．Because a microblog doesn’t include pictures, but a traditional blog does.

B．Because a microblog doesn’t include videos, but a traditional blog does.

C．Because a microblog has smaller contents than a traditional blog in actual and total file size.

D．Because a microblog can only be written on the cell-phones.

Microblogging can protect the following privacy EXCEPT_______.

A．deciding the readers of the microblogs

B．allowing readers to publish their views

C．readers’ deleting what a microblog says

D．deciding whether readers can enter it

We can infer from the passage that______.

A．microbloggers always post about the thematic topics instead of the simple ones

B．microblogging has developed so quickly and brought the owners more and more benefits.

C．microblogging protects both the owners’ and the readers’ privacy

D．the studies by Harvard Business School have analyzed the usage of microblogging services