blogs on market, sale, brand, startup

No. 1: From the horse's mouth

Harvard Business Review: hbr.org
If you want to learn more than an MBA, why not start with people that run a business school? Harvard Business Review provides advice on finance, business models, company culture, tech, and more.

No. 2: Marketing

Seth Godin's blog: sethgodin.typepad.com
This legendary blog, like the man behind it, provides a fantastic and nuanced perspective on everything from marketing to motivation. Beyond practical advice, it also teaches you to think differently and approach business with an open mind.

No. 3: Entrepreneurship

Fred Wilson's blog: avc.com
A venture capitalist since 1986, Fred Wilson shares his considerable experience in VC, general business, and startups--particularly tech. A prolific writer, he has posted every day since 2003, and amassed a large following of insightful commenters who provide almost as much useful information as the blog itself.

No. 4: Customer experience

PeopleMetrics: peoplemetrics.com/blog
The PeopleMetrics blog does not omit a single facet of customer experience, with case studies and actionable advice that will help vastly improve the attractiveness of your business. Its writing staff is composed of practicing customer experience management experts, who rely not only on their previous experience but also on what they're learning in current engagements.

No. 5: Branding

Strongbrands: timcalkins.com
Run (as its URL suggests) by Tim Calkins, a clinical professor of marketing at the prestigious Kellogg School of Management, Strongbrands provides clear, straightforward examples. Calkins uses the blog to examine branding initiatives, challenges, and developments as they come about. This blog is a fantastic resource for developing a sense of how branding plays out in the real world.

No. 6: Sales

Aaron Ross's blog: predictablerevenue.com/blog
Ross, writer of the No. 1 best-selling book Predictable Revenue, combines practical advice with more personal posts, keeping readers informed and inspired. Like the writers at PeopleMetrics, he uses real examples from his consulting experience to demonstrate the principles of effective sales.

Honorable Mention

Further Research: The Personal MBA: personalmba.com/best-business-books
Blogs are a fantastic way to quickly get up to speed on current developments in the business world, and see practical applications of business concepts. But depth is required as well as breadth, which means a more thorough understanding of business fundamentals is paramount. If you are looking for general knowledge, The Personal MBA reading list is a fantastic starting point. It includes recommendations for books on value creation, marketing, sales, finance, management, and much more. It is truly a one-stop shop for your educational needs.
Of course, this isn't a comprehensive list, or even a definitive one. There are tens, hundreds, thousands of blogs on these topics, and ultimately you have to find the resources that work for you. Everyone has different learning styles, and only you can know what fits your needs. But the blogs on this list will give you a strong starting point from which you can build your knowledge base and develop the mindset needed to succeed in business