The nature of a search engine is to derive the value of your content from the content. Therefore, focusing on your content is a far greater return in value than focusing on trying to draw the attention of a search engine to tags, meta data, or URL paths. Not saying that those things don't contribute, but I'm not certain that the ROI is worthwhile.
Think of it like a resume. If you have the talent and background to put on a resume, you'll get consideration. You don't need to spend hours upon hours refining it to add just the right trendy keywords or ordering things in the most appealing way to automated resume readers. On the other hand, if you have little to offer and you are concerned that you'll be weeded out quickly as a result, you can substitute your background and experience (content) with keywords and other tricks to try and get beyond the initial weeding out. Kind of a tactic of desperation and lack of confidence.
I do have a strong bias against the whole SEO thing. I won't pretend that I don't. I'm put off when I hear people focusing on it rather than content and it makes me think of greasy, scummy, snake-oil salesmen. Guys on late night infomercials trying to convince you that you can skip everything and get right to becoming rich and famous by thumbing through their special book and employing their special techniques for flipping property with only two hours of work per week.
This is probably a very unpopular opinion to share around a group like this, but what can I say?
I'm biased as a developer who started a site that ranked top 3 for about 5K very competitive long tail phrases. So I've seen first hand the enormous benefit of allowing some time/effort/thought toward usability for bots.
It's not a given that Google will just "figure it out" and your reward will be in heaven. Anyone who thinks that is just hoping Google will do their job for them.
The upside for me is not having to work for the man thanks to selling the aforementioned site.
i imagine in Google's perfect world there is little or no room for SEO. doesn't that mean it actually is Google's job?
The rest just read and regurgitate the results of those experiments when the experimenter decides to release those results (ie when it's not too much of a competitive advantage).
http://www.codinghorror.com/blog/2008/10/the-importance-of-s...
This is pretty much what SEO people mean by white hat SEO. Create interesting/valuable content that people will link to, and you will be rewarded in search engine rankings.
I am totally not saying this wearing my consultant who wants your money hat: you often will make repeated investments in getting this right, have no discernible success with some, and continue having to do so for forever as your business evolves. It isn't a matter of tweaking titles once and getting back to "real work."