I was wondering how important W3C validation is when looking at how google ranks a website. I have one particular site which has been online for around 3-4 months. All the content is great and it is a rank 1 PR site however I recently noticed that there were quite a few errors (mainly ampersand), and although completely invisible to the naked eye, this was causing quite a high percentage of my websites pages to fail validation. The website has no problems and everything works fine and is how it should be apart from this single problem. Is it worth taking all the time to correct these errors or will it not make any kind of difference to google or any other service i may be unaware of. Is the W3C Validation tool just supposed to be a guide or should webmasters always try to validate? Thank you