I was out about this weekend and was asked on more than one occasion why I blog. I blog for a number reasons. Some personal and some professional.

On the professional side:

1. It demonstrates expertise knowledge and expertise in chosen skill year.

2. Increases Google page ranking and key words with relevant fresh content.

3. As a sales marketing tool, to build references through comments and the online community for consultancy work.

4. Generate income through paid advertising.

On the Personal side:

1. As a personal development log

2. to give help and give something back to people trying to understand and use this technology

3. For personal enjoyment of developing writing and pr skills

Chris Brogan is highly accomplished writer and blogger he had this advice to say about blogging in different media spheres.

1. If your goal is to be an entertainment or news blog, be very clear that it’s that and not a “fun” blog. Consider splitting off your personal or fun blog.
2. If your blog is to be your business, treat it like that. Get into stats. Get into building audience. Get into delivering something unique. Don’t straddle back and forth on this.
3. If the goal is to be a great community resource, mix your blogging time with time spent reaching out to the community you propose to serve. If that’s an offline opportunity, like something local, be there. Be active. Be a connector.
4. If you’re going to be a professional about your blog, carve out the time to do it right. Never, ever, ever post a “sorry I haven’t posted lately” blog post again. Ever.
5. Up the ante on delivering original material. Get outside the echo chamber. Writing a me-too blog isn’t the way to build your blog to the levels you seek to attain.
6. It’s okay to use a personal voice. In fact, there’s no point blogging if you’re going to write like a cold robot. But keep personal and useful in balance.
7. If you are attempting to do real business via your blog, look for ways to convert readers into customers.
8. If it’s just an ad revenue business, compete, and be honest about that. Compete with others in your space for audience, value, and better deals. My point in this regard is that going halfway into the water doesn’t make you less wet.
9. If your blog is the premier source of information for nonprofits, for photographers, for whatever, then be sure you’re scouring news feeds and finding information outside the blogosphere to keep that relationship informed.
10. Make a point of engaging your community often in the comments section, on their blogs, on the other social networks where you cross paths.

chrisbrogan, 50 Ways to Take Your Blog to the Next Level, Sep 2008