Have an Answer?
First of all, that's a business with few barriers to entry and lots of competition, meaning it's hard to make moneyespecially as a startup. (Here's a good read on the economics of online content: http://blogs.reuters.com/felix-salmon/2013/02/20/content-economics-part-1-advertising/)
If you're really set on that field, I'd recommend first trying to get a job at an online or social media outlet, because you'll learn tons more, and more quickly, than you would any other way. There's lots to learn: content management systems (CMS), blog and web platforms, APIs maybe, editing, writing, graphic design, Internet hosting, search engine optimization (SEO), marketing, sales, accounting, legal (e.g. copyright, libel, slander, fair use), etc.