Depends on how rigorous plugin developers are with their code.

Although validation doesn't really mean much, apart from how closely developers followed standards.

Have you ever validated Google, or YouTube? They're full of errors!

Topic was moved from General Questions.

Quote from Kostia Hy, just tested my site on  http://try.powermapper.com/Demo/SortSite  and saw a lot off issue/errors.. 90%.  dont know if this page ( powerpaper) shows well but then i check another site from my countrie ( most popular) it show 30.. 50..or even ~20 proc.

I asked this a few weeks back and you need to remember with something as complex as Oxwall following W3C is just not going to happen. This will not break your site. What are you worried about in these errors keep in mind errors can be as small as not adding "alt=" to your html photos which allows the photos to be seen in a text format if for some reason someone can't see it.

Not all errors are fatal similar to forgetting the salt in your dinner this dose not mean it's not good anymore just 10% less sodium XD