Yes, they are really typing things like that into search engines. Seriously. I have done the research and just gave a talk on stats. You would be amazed at what people type into search engines; they think it's the Oracle of Delphi.
There can be more than one URL for a given post, especially if you've got the domain name upgrade. If you hover your cursor over each entry, you can see it (at least in my IE6 you can) down in the bottom left hand corner, and you'll see the differences, like raincoaster.com/what-in-gods-name and raincoaster.wordpress.com/what-in-gods-name and there are other variations as well. They all do reference the same post, though, that's the important thing. There's information there about how people came to the post, but unless you're going to go wild reading the entrails of the stats page you needn't bother trying to work it out, it's very esoteric.
I'm not sure I follow the second table, but you seem to be saying that different search strings that should all lead to the same blog post have different numbers, is that right? Different search strings have different success ratios at finding your blog posts, and so do different search engines. My searches right now are virtually all "Helen Mirren Topless" I kid you not, but the reason they have different numbers is that some are in quotations and some from Google and some from MSN and some from Yahoo and some from god-knows-what. They all register as different search results on your stat page.
When you're seeing near-identity throughout your search string stats, it means that your blog is ranking very, very high in many search engines for that particular search.
Does this make sense? I've only had two hours of sleep and am not sure I'm even typing in English at this point.