Here's a list of awesome online marketing blogs that will teach you how create shareworthy content, market that content, and build your online presence!
Copyblogger is a site that anyone serious about creating better content should have bookmarked. Filled with actionable posts, interviews, and great tips, Copyblogger is an excellent resource.
One of the best ways to learn is by looking at the successes/failures of others. Niche Pursuits puts it all out there with a ton of real life case studies they conduct, and interviews with successful online marketers.
Smart Passive Income is run by one of the most well known online marketers out there, Pat Flynn. It's geared towards the creation of niche specific sites, but the tips and info is relevant to anyone in online marketing.