I am looking for a comapany that focuses on marketing on the internet. I do not need any other more traditional forms of marketing.

I am 24. I play guitars (advanced) and the piano. I am good at programming and puzzle solving. I am pretty much everything a perfect computer geek needs to be. I am planning to start off a company before which I will need to get a feel of how marketing works on the internet. I would like to create niche blogs but I don’t see where I should start and what topic would be ideal for me. Could you suggest a way for me to get things going.