This is quite straight forward.
Everyone enjoys doing what they enjoy, and when they do find something they enjoy, they can usually talk about it all day given the chance! I have a friend who really enjoys Peking (Beijing) duck, and whenever he cans (and that's almost all the time) he will talk about Beijing duck that he had just eaten from a new or usual restaurant he goes for the duck.
And the thing is, he will be very detailed in his descriptions, such as "the crispiness of freshly fried duck skin", the "mouth-watering savoury sauce", "the melt in your mouth sensation of the duck" and the like, which also causes most of us to start becoming hungry and wanting to eat a Peking duck too.
That is his passion, and love.
Which is why, when translated to a blog, I would strongly recommend you to blog about what you love to do or talk about, as then you would enjoy doing it day and night, there's a strong compliance and motivational factor which will keep you going.
Also, people enjoy listening to other people sharing about something they enjoy, and will consider listening to you when you recommend doing something you enjoy.
Hence, whenever my Peking duck friend recommends a restaurant's Peking duck, we'll end up trying it, as we are already half-sold on his passion for the duck.
People flock to people who are enjoying themselves, and on a blog, when you enjoy yourself writing about it, people will come and stay for a few reasons.
When people see passion and sincerity, they want a piece of it too.
Secondly you'll attract people who tends to become your community (you call these people friends and target audience), and they are likely to share your likes too.
And that is what we want to achieve - being true to ourselves and our passions, and attracting like-minded people.
No point attracting hi-and-bye crowds, as they'd not be interested.