These are UNTRUE, many people think these are true, or at least some of them. But they are not. So you don’t have to do it for getting higher ranks in search engines.
- Outbound links improve your ranking
- Submitting your site to the search engines too many times will get you banned
- Links from .edu sites are worth more then from other sites
- Pages with .php extensions don’t rank as well as pages with .html extensions
- Search engines won’t index pages with query strings/all query strings are not search engines friendly
- Using seo software gets your site penalized
- Hyphens are not needed to separate keywords in a domain name or URL
- Too many hyphens in your domain name will cause the search engines to label your site as spam
Hope this is useful information for some of you.