Can someone ellaborate on WordPress.com?

[Jo Han]

1) No, you don't have to have any knowledge of HTML at all. * (see #3 below)
2) Yes, it is completely free. There are many free plug-ins and templates available as well, but there are also premium ones which you are required to pay for if you want to instal and use them. For basic purposes you will likely never need them.
3) * Depends... Will you be hosting your own blog, or just signing up for a free blog on the wordpress.com website? If you sign up for a blog hosted on wordpress.com then there is nothing else you need to do, besides going through all of the settings and setting it up like you want it. If you are going to actually use your own hosting (as in, you have your own ".com" website which you pay a monthly fee for), then you will need to follow the setup guide and you *may* need to know how to set permissions on directories and how to use FTP.