Traffic vs. SEO?

Hey guys,

I have a couple of questions I'd like your opinion on regarding traffic and SEO.

In all, I think traffic strategies can be divided into three categories:
1. Direct advertising (things like mingling in forums, doing some "conversational" marketing, also guest blogging might be another example)
2. Free / SEO
3. Paid

I'd like your opinion on the following questions:

1. Would you consider promotion using multiple methods, or would you only use only one of the above for any one project?

2. In the context of SEO, would you consider using automated software like SEOLinkVine, Bookmark Demon, SEMRush, Traffic Kaboom, SENuke - do these actually produce the results they claim they do (high rankings in short periods of times), or do you prefer to spread it out over a period of time and do these manually or outsource them?

3. How do you distinguish between SEO and "driving traffic"? Do you use SEO to drive traffic or do you drive traffic while using SEO as an aspect to boost traffic? Are these interchangeable? I ask this because many times over, gurus say "don't rely on search engine traffic...diversify your traffic sources", yet the majority of traffic to websites still come from search engines, and not Facebook or Youtube, regardless of how times change. Also, I have rarely seen a traffic course that doesn't mention SEO.

4. Therefore, last of all, when driving traffic, do you write articles, create videos, generally, create content that targets search engines or humans? Which is more important?

Thanks for your input!

Cheers,
Baggio.