We live in an age of social media. The day when a writer could write in obscurity and be a successful well read author is gone.
Reality TV takes us into the private intimate daily lives of previously unknown people. Paparazzi get paid a lot of money for exclusive photos of celebrities on vacation. Face Book, Twitter, and blogging connect fans with their idols and readers want to connect with their favorite authors. But most of all, publishers want to know you have a following or fan base of which a decent percentage are going to buy your book.
"I just want to write", you say.
But blogging, tweeting and posting on Face Book is writing. It's just tighter writing.
If you are a nonfiction author, you will share your expertise and offer general helpful advice. Be careful never to offer personal counsel. If asked, direct them to an outside resource.
You historical fiction authors might share things about your research process or real events that took place in various geographical locations you have woven into your stories. Or share what you felt emotionally when walking in your character's shoes.
Remember- social media is social. Get to know others with similar likes and friend them on FB and follow them on twitter. Read their blogs and comment if you liked what you have read.
Transparency will endear you to your readers and 'friends'. What interests you will interest others. My post about my grandmother's iron skillet reaped 75 comments and prompted a delightful discussion.
Be honest but keep it lighthearted. Express your opinion but don't put anyone else down to do it (it will end up making you look bad).. Unless your life's mission is to change another's political persuasion, stay away from posting anything related to politics. Don't restrict your readership!
BTW statistics tell us a few pictures raise the blog's likability for a more pleasurable read. Which in turn might lead to faithful blog followers.