You're not derailing anything, I'll answer any questions I'm able. As far as people not "giving away" their keywords, the point I'm trying to make is that most of us have no idea what keywords they are focused on because they've never thought beyond the "It would be cool if I could rank for (insert high value keyword here)" There is no plan in place. That's why the series I'm doing on my blog right now is so important, you need a plan for your SEO.
As for the specific questions you are asking, I'm trying to answer these my SEO plan series but here's an outline.
Having your keyword in your title = good
Repeating your keyword over and over in the body of text = bad. Keep it conversational.
Having your Keyword in your URL = Very Good
Having keywords as categories = Undetermined. Every time I see a report that it has a positive effect on SEO, two weeks late another report comes out that says it has no discernible effect. It's never been found to have an adverse effect so I would still use good SEO policies when selecting categories.
The "having keywords in the first paragraph" thing is old SEO tactics. When Google was just starting they would give more weight to what was "above the fold" to use a newspaper term but now they are fast enough that they can see the whole site.
Obviously the best SEO tactic is to put out relevant content on the term you are focused on, what I'm trying to do is to get blog owners to pick a term and actually focus on it instead of just writing whatever and hoping for the best. It's been said that to fail to plan is to plan to fail and it's very true.
