• for <applet> tag, the equivalent tag is <object>
• for <center> tag, the alternative CSS property is text-align
• for <font> tag, the alternative CSS properties are font-family and font-size
• for <s>, <strike> and <u> tags, the alternative CSS property is text-decoration

• Deflate is an option which comes automatically with the Apache server and which is simple to set up.
• GZIP on the other hand needs to be installed and requires a bit more work to install. However, GZIP does achieve a higher compression rate and therefore might be a better choice if your website uses pages which have a lot of images or large file sizes.

# compress text, html, javascript, css, xml:
AddOutputFilterByType DEFLATE text/plain
AddOutputFilterByType DEFLATE text/html
AddOutputFilterByType DEFLATE text/xml
AddOutputFilterByType DEFLATE text/css
AddOutputFilterByType DEFLATE application/xml
AddOutputFilterByType DEFLATE application/xhtml+xml
AddOutputFilterByType DEFLATE application/rss+xml
AddOutputFilterByType DEFLATE application/javascript
AddOutputFilterByType DEFLATE application/x-javascript

<IfModule mod_expires.c>
    ExpiresActive on
 
    ExpiresByType image/jpg "access plus 1 month"
    ExpiresByType image/jpeg "access plus 1 month"
    ExpiresByType image/gif "access plus 1 month"
    ExpiresByType image/png "access plus 1 month"
</IfModule>

RewriteCond %{HTTP_HOST} ^www\.example\.com$
RewriteRule ^/?$ "http\:\/\/example\.com\/" [R=301,L]

RewriteCond %{HTTP_HOST} !^www.example.com$ [NC]
RewriteRule ^(.*)$ http://www.example.com/$1 [L,R=301]

• replace the at (@) and dot (.) characters
• replace text with images
• use email obfuscators
• hide email addresses using JavaScript or CSS trick

<link rel="stylesheet" media="screen and (min-width: 480px) and (max-width: 960px)" 
href="480-960.css" />
 
<!-- OR -->
@media screen and (min-width: 480px) and (max-width: 960px) {
    #header {
        display: none;
    }
}