I've been researching various methods for SEO where pages have precise titles, keywords are highlighted with h tags and tick the many boxes stated in good page mark up for SEO.

However when looking at some top ranked search sites on google for key terms they have terrible SEO based mark up. Really long page titles, no tags, limited appearance of keywords in the text and so on. SEO analysis services rate them lower than other sites, yet these sites rank really high. Even with a low number of back-links they are high, so I don't understand how these sites earn the position when they appear inferior to those below them which have better mark up and links.

I don't want to cause trouble my mentioning sites or keywords etc. but looking in google at 'executive search' the roughly 5th placed site makes no sense why it should be highly rank, especially with all the added .swfs. The same applies for the top of 'Japan Executive Search'.

My main point is that these sites seem to not have all the important structural rules stated in seo page rating applications and general suggested best practice, nor do they show large back-links.

It makes me feel like there is no point bothering to write decent mark up if it really doesn't matter.

Can anyone explain how sites with such mark-up, and low back-links can outrank well written and structured sites with greater linkage?

Sorry if this is a fuzzy question, I want to avoid singling out any sites for example, but it really has me perplexed that sites which appear to ignore the suggested best practices rank so well.