SEO and HTML Character Entities
Make sure your information is processed correctly in searches, marketing emails, blogs and the product listings in shopping sites by validating your HTML, especially the special, non-standard, or foreign characters. There are many special HTML entities, including quotation marks, apostrophe, ampersand, numerical marks such as less-than and greater-than, currency symbols, foreign alphabets and accent marks, copyright and trademark symbols, superscripts and fractions. Search engines may differ in the way they handle HTML entities in search processes and may have trouble displaying or converting search information with special or newer html characters.
This is important in regards to the metadata in your HTML meta tags. The use of numeric character code in the Meta tags is recommended to avoid potential problems. Use HTML entity codes since programs may not recognize all the character entity values which are part of the html standard nor the ALT+NUM method of displaying ASCII characters. Do not expect special characters which you paste directly into HTML documents to display or be searched correctly either.
For example, the apostrophe may not display or be recognized by programs correctly, so the actual code for it should be placed in your Meta tags. And if you are using accent marks or foreign language letters, the same action is recommended.
Some HTML Entities with Entity Codes: