Why so? Do you think marketing is not a real job?

It's PR, but on the web. Unless PR is also not a job?

Lots of companies use social media as an outreach channel to their readers and users. From Tmobile's offering of tech support over Twitter, to live tweets of news events by journalists in the field.

I can guarantee you, every large corporation has a social media team, possibly a sizeable one, and the people working there are kept very busy.