Compliance

Greetings to you,
 
I work for a small webdesign business on the beautiful west Coast of Scotland and we always take great care and spend time ensuring that the sites we create for our customers are fully compliant with W3C and contain no IIS violations. This is done in the belief that, not only is it important to do things correctly and "keep a tidy house", but, more significantly, I understood that too many such errors and violations would result in those sites being adversely considered by the Search Engine algorithms and consequentially being penalised in the rankings. 
 
As part of a recent promotion, however, we have been offering a free web analysis for other sites. During these analyses, we came across a site which had over 300 W3C errors and some 3500 IIS violations - and all this in only 15 pages or so. Astonishingly, however, this site was doing very well in the rankings for relevant Search Terms.
 
It would seem that Consortia like W3C are valiantly creating standards to improve the internet industry but, as yet, the major search Engines are not paying much heed.
 
I appreciate that you cannot give me a definitive answer and I have no wish to discuss individual cases but please can you give me an indication of just how much importance is being ascribed to these errors and violations in the relevant algorithms. I do not imagine they are ignored completely but, on the other hand, there does not appear to be any significant advantage in taking the care to ensure sites are compliant.
It may all be part of a more gradual process, of course, in which case I will be glad to be prepared for the future - forewarned is forearmed after all.
 
Thank you for taking the time to consider my enquiry. I look forward to receiving your response.
 
Kind Regards,
 
Irene
Argyll Technologies