I have a question which may seem ridiculous but I think it might actually matter. If you have your text as ONE LONG line of code. -----------text----------text-------------> Like that. Versus multiple lines |----text----text---| |----text---text----| |---text---text-----| Same amount of text, just differently coded. You get the idea. Does it matter that the text spans multiple lines instead of one long line? I know search engines will still "read it the same" But if you have 100 lines of code and 1 long line of text, would it screw the code-to-content ratio and hurt your serps? It's probably ridiculous, but I'm starting to wonder...
I suspect that it would matter not a bit to the SE's - other than perhaps a slight skewing of code-to-content ratio if they consider whitespace content, which is doubtful.
I think it does matter, especially with CSS files etc. Also, neat code can considerably reduce the file size, which will save you a lot of bandwidth and also load the pages quickly. You can achieve all this by removing extra new line characters, and properly formatting the source code.
Certainly the bandwidth savings can compound itself into dollars on a popular site, and save load time on large pages, but I think the question was in relation to search engine rankings. I concur that good coding practices make a huge difference in a great many areas, but I sincerely doubt that content structure has anything to do with SE rankings. Perhaps all things being equal, the better performing site would get the edge, but page size and page load times will not significantly change due to coding practices unless your existing coding practice is EXTREMELY verbose. That said, getting everything nice and neat into 8k packets can work out nicely for dial-up users.
Some search engines only looks only first 500 to 600 lines, At that point we must consider the coding way
At one point, one of the SE's only indexed the first 150K of a file - I forget if it was Yahoo or Google, but I don't think that's a valid statement anymore. I remember recommendations out there to keep your sitemap files under that limit. I've never heard anything about line limitations though. Seems like a silly concept.