First, I haven't made it all the way through the thread, but it's great so far and hopefully I'll have time to make it through later on...
One of the things that 'jumps out at me' is it seems like I'm reading: 'I changed [blah]', 'then I did [blah blah]', 'then I tried [blah blah blah]' ... Only an SEO would do that.
Normal people don't change things, then quickly change them again when the changes don't have the immediate desired effect on rankings, but one of the things stressed wrt rankings over the years is time/longevity of a site (IOW Patience), which makes me wonder if reacting too fast is part of the issue, because changing and changing back or changing again when rankings change (for the negative) is something only someone who's watching their rankings and trying to control (manipulate) them would do.
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Let me put what I'm thinking another way with a couple of questions...
How many times do Wikipedia, eBay, Apple, Amazon, eHow, CNN and all the Mom & Pop site builders who don't know SEO change the title of their page(s)?
How many times have you?
The 'big boys' (from what I've seen) 'get it right the first time' and leave it alone. (Yes, some may change occasionally, but go with the point on this one.) Mom and Pop who don't know SEO set it and forget it ... An SEO is generally the only one who makes changes to something like the title of a page.