If you want to find out how to learn SEO online then it seems like it's a topic that's fairly well-covered as it is. I mean, there are sites like Moz.com, Search Engine Journal and so on. But as it turns out, they are more about the in-the-trenches practices and advice for people who are already deep into SEO. But what if you're just starting out?
Here's the core of the problem. Too many businesses (online and offline) tend to focus only on getting new customers and forget about taking care of the existing ones. For instance, have you ever seen a TV ad of a mobile network in which they're announcing that everyone who signs up for their services will receive a new iPhone for $10 (or something similar)?