You can highlight them while your reading to go back to them later, so yes if that answers your question. I'm not sure if you can just search beforehand without previously reading the text. I'll have to look into it though. It is a pretty cool device.
I'm a newbie here, but Ham on Rye starts off in childhood, so it makes sense to me that it's the first book. I didn't know, initially, that the stories run in chronological order. I just picked it randomly.
You can on a Kindle, I have to assume you can on any of the others as well. I think they're a great way to read books that you don't really need to have (or care about having) on a shelf somewhere. That being said, there are still books I want to have on my shelf.
Funny though, the Kindle has had the same effect on my book reading that the first VCRs had on my movie watching. That is, I rarely watched movies before the VCR, but once I got one, I found myself not only renting tapes, but also going to the movie theater. On the Kindle I read books that I would never drive to a book store to buy. Things I want to read, but I just wouldn't have bothered with before.