I think Google did pretty descent 'clean up' recently. Some spammy sites that were often to be found on the page 1 are not there anymore. Some of them are getting there if there no other competition at all, but it does not happen too much now.
Yes i have also faced many problems like this before. This type of problems are irritating and disturbing for oneself. When in urgent work you are hampered by this sort of disturbance which delays your work and wastes valuable time.
Because the algorithm is crap and the sad truth is. If your domain is old, and has a lot of backlinks from the past you can do almost everything you want and your content will rank fine. It just doesnt matter what you write with such a domain. If your site is new... hire some professionals..
Hi. Yes. Some websites are like that. Just a site with advertisements and no content. I believe that websites like that don't last longer. I also visited some sites like that and they disappear after 5 days or even earlier than that.
I would encourage you to tell google about spam, scrap, redirect and other no-content sites https://www.google.com/webmasters/tools/spamreport In fact, use chrome and download the "google webspam report" plug in. Then all you have to do is click "report spam" to open a spam report. Usually if you find one of these pages it is in a website with millions of others, so alerting google to them can make a significant contribution. Occasionally I take phrases from our web site, put quotes around them and do a search for autoscrapers. Then I report them to google, hoping for a glorious resurrection. Also, you might notice that the first thing you can report on the webspam report is This page is selling or buying links. wiz
seo is not about w3c compliant, it's about how the search engine serve the searcher with a good content.. and that old rubbish website still on the top search engine since they maintain a good back link, not link spamming and get backlinks from trusted and high PR website.
Either Google "likes" them or they have done something with seo to get rankings such as lots of backlinks, etc. It could also just be a temporary anomaly. Google will catch up to them, eventually. If it really bothers you, report them, go into your google webmasters account (register for one if you haven't already) and complete the form.
What is the reason why it is bothering you so much?Just curious, are you talking about one of your competitor's site? And about "full w3c errors, lot of links, less contents". Some sites can still be useful for visitors even if they have many links. For example, one of sites that I Love and Hate at the same time is 411 dot Com site. I am always using them to find an info about somebody's address or phone number, but the amount of advertising they have on this site (and how annoying this advertising is) is driving me crazy sometimes. Too much commercials? Yes! Is is still useful. Yes.
SEO is a dynamic beast, and sites may come and go on the first page of the results. It's a moving picture, not a snap shot. Track the placement of a site based on its keyword over time and you see it bouncing all over the place, as Google dance or a competitor seeks to out rank it through better backlinking or other tactics.