How necessary are DOCTYPE tags?

[DXL]

Does it negatively affect my site in search engines because I don't have the DOCTYPE tag in there? I don't have it on any of my sites, I'm wondering how much of a difference it actually makes.

[kaled]

It is unlikely that search engines care about doctypes. However, by their absence, you are implying that no attempt has been made to validate the code. Invalid html may confuse search engines.

At the very least, critical pages should be validated.

Kaled.

[DXL]

How does it confuse the search engines?

Also, I just noticed someone with this tag:

<meta name="rating" content="Safe For Kids">

Do the SE's collect info on what a kid-friendly site is? Would that affect traffic as well?

[DanA]

With syntax errors, the search engine might index html code or look for a closing tag or consider the middle of the page as its end...
Major search engines do not care much about "safe for kids" or other meta tags.

[DXL]

Ah, I get it now. So assuming I can search for a few random lines in various areas of a critical page and it shows up in the search engines, should I consider the page okay even without validation?

[keyplyr]

Using a complete DTD (with the link back to W3C) ensures your mark-up will be rendered in Standards mode.

Related thread: [webmasterworld.com...]