W3 Total Cache

W3 Total Cache is currently considered on of the best top 3 caching systems for WP sites.

It is used in many famous commercial websites like Envato, Mashable, Tuts+ Network and more.

Installation:

Unpack and upload it to the /wp-content/plugins/ directory.
Activate the plugin through the 'Plugins' menu in WordPress.

Features:

• Can cache on disk
• Can cache in-memory
• Can cache on CDNs
• Can cache pages
• Can cache posts
• Can cache JS and CSS resources
• Can cache database objects
• Optimized progressive render
• Reduced HTTP requests
• Reduced document load time
• Increased visitor time on site
• Saves bandwidth
• HTTP compression for HTML, CSS, JavaScript and RSS
• Helps scalability
• Transparent content delivery network (CDN) integration
• Non-blocking JavaScript embedding

What is new in this release:

• Fixed undefined w3tc_button_link
• Fixed support and other form submissions
• Fixed extension enabled key error
• Fixed Test CDN errors
• Fixed trailing slashes in custom wp content path and Minify
• Fixed WP_PLUGIN_DIR not being available when object-cache.php is loaded and W3TC constant not set
• Fixed Minify Auto and restructuring of JS code placement on page
• Fixed remove / replace drop in file on plugins page
• Fixed false positive check for legacy code
• Fixed deprecated wpdb escape
• Fixed Fragment Caching and APC anomalies
• Fixed cached configs causing 500 error on interrupted file writes
• Fixed readfile errors on servers with the functionality disabled
• Fixed false positives for license key verification
• Fixed debug information not printed on cached pages
• Fixed backwards compatibility and flushing and added doing it wrong notification
• Fixed "Prevent caching of objects after settings change"
• Fixed "Use late init" being shown as enabled with Disc:Enhanced
• Fixed missing param in APC cache method declaration
• Fixed user roles property not begin an array
• Fixed adding empty Vary header
• Fixed notice on failed upgrade licencing check
• Fixed Database Cache description text
• Fixed duplicate bb10 agents
• Fixed settings link in Minify Auto notification
• Fixed notice with undefined constant
• Fixed nginx configuration and Referrer, User Groups setting
• Fixed Genesis settings and Suhosin field name limit error
• Fixed Genesis and Fragment Caching (caching categories etc)
• Fixed CDN being enabled when creating NetDNA/MaxCDN pullzone
• Fixed NewRelic related notice in compatibility popup
• Fixed trailing slash issue in filename to url conversion
• Fixed issue with wp in subdirectory and relative Minimal Manual urls
• Fixed issue with widget styling
• Fixed issue with Purge All button action
• Fixed issue with exporting of settings
• Fixed issue with plugin interferring with preview theme
• Fixed issue with malformed config files
• Added caching of list of posts pages (tags, categories etc) to Genesis extension a long with flush it checkbox
• Added typecasting on expiration time in object cache drop-in
• Added capability check for save options
• Added FeedBurner extension
• Added woff support to Browser Cache

What is new in version 0.9.3:

• Added support for extensions
• Added support for WordPress SEO image filter and CDN
• Added file exclusions for media query string logic
• Added user agents to user agents groups
• Added CDN FTP path / host test
• Fixed object cache and database cache for localization plugins
• Fixed chinese filenames when using CDN
• Fixed removal of stale cached files
• Fixed missing slashes in inline HTML, JS and CSS files when using CDN
• Fixed auto mode of minify filename length test
• Fixed NetDNA / MaxCDN testing when domain does not match domain zone settings
• Fixed CurlException and NetDNA / MaxCDN
• Fixed pull zone dropdown not showing or showing wrong zone
• Fixed trailing slash and redirect with apache
• Fixed false notification for page cache rules verification
• Fixed duplicate notifications for FTP

What is new in version 0.9.2.10:

• Added NetDNA / MaxCDN dashboard widget
• Added zone dropdown for NetDNA and MaxCDN CDNs
• Added create pull zone for NetDNA and MaxCDN CDNs
• Added notification(s) if incompatible plugins are detected
• Added "Disable CDN on the following pages" setting
• Added "Disable CDN on SSL pages" setting
• Added late init support for page cache's fragment caching
• Added POT file
• Added translations NL, PL
• Fixed setenvif issue in htaccess rules
• Fixed failed rewrite (404) and not caching feeds in nginx
• Fixed NetDNA / MaxCDN CNAME purging issues and "Test CDN" functionality
• Fixed Azure container handling
• Fixed New Relic verification
• Fixed theme preview
• Fixed wrong path issue with w3tc-wp-loader.php
• Fixed auto mode of Minify and filename lengths
• Fixed purging monthly archives with Varnish
• Fixed insert, delete, update quries purging with database cache
• Fixed HTTP compression when dynamic page fragments are used
• Fixed PHP_STRING and other warnings
• Fixed case sensitive header detection
• Fixed HEAD request handling
• Fixed event scheduling propagation in Multi Site
• Improved CDN custom file paths
• Improved handling of legacy config files
• Improved NetDNA / MaxCDN alias, key, secret string handling (backwards compatible)
• Improved auto mode for minify file naming which was causing unncessary issues
• Improved handling of hardcoded WordPress paths
• Improved the file management functionality (FTP support, file permissions etc)
• Improved disk cache directory usage
• Improved garbage collection of expired cache files for disk enhanced method of page caching

What is new in version 0.9.2.8:

• Fixed /tmp file creation issue when saving settings
• Fixed an issue with auto minify
• Fixed an issue with New Relic API key verification
• Fixed uncommon issue with require ObjectCache failing
• Fixed uncommon open_basedir verification issue
• Improved notification handling by modified WordPress FileSystem API implementation

What is new in version 0.9.2.6:

• Added more options for placing minified files on pages. Custom placements using HTML comments.
• Added CSS inclusion for auto / manual minify. If present its used:
• Added JS inclusion for minify auto mode. If present its used: ,
• Added JS inclusion for minify manual mode. If present they are used when selecting correspong location in placement dropdown: , ,
• Added new minification inclusion options, async, defer, extsrc and asyncsrc
• Added flushing sitemaps
• Added flushing custom pages
• Added flush the current blog when flushing in MultiSite
• Added flushing home page and/or post page if static

What is new in version 0.9.2.5:

• Fixed security issue that can occur if using database caching to disk.

What is new in version 0.9.2.4:

• Added support for Microsoft SQL Server
• Added API support for MediaTemple ProCDN (EdgeCast)
• Added set_time_limit to self test
• Fixed LiteSpeed web server support
• Fixed native hostname 301 redirect
• Fixed redundant object origin push export
• Fixed WSOD (white screen of death) caused by minify in some hosting configurations
• Fixed text encoding in feeds
• Fixed incorrect mime-type in feeds (which caused feedburner anomalies)
• Fixed array to string notices
• Fixed expires header support for AWS
• Fixed minification of font-family
• Fixed object cache write issue in WP Admin
• Improved (reduced) memory utilization by up to 70%
• Improved disk enhanced page caching performance
• Improved object caching performance
• Improved activation reliability
• Improved reliability of minify auto mode
• Improved security (added nonces, no directory indexing, prevent direct file access)
• Improved compatibility with network based file systems

What is new in version 0.9.2.2:

• Fixed bug with minify directives, e.g.: "File param is missing," causing minify caching to fail
• Fixed bug with document root detection for IIS server
• Fixed bug with HTTP compression when using CloudFlare
• Fixed bug with HTML validation with JavaScript embed tags
• Fixed bug with fancy permalinks, sites with or without trailing slashes can now cache pages using disk enhanced
• Fixed bug with appending WP_CACHE define into wp-config.php for some users
• Fixed bug with path to JSON.php
• Fixed bug with listing of buckets error with AWS S3
• Improved compatibility with WordPress SEO by Yoast, 404 error exception list sitemap value changed to: sitemap(_index|[0-9]+)?.xml(.gz)?

What is new in version 0.9.2:

• Added support for nginx web server
• Added support for CloudFlare
• Added origin pull support for Amazon Cloudfront
• Added Microsoft Azure Storage support for CDN
• Added WinCache opcode cache support
• Added additional minifier engines for HTML, CSS and JS including: HTMLtidy, CSStidy, Closure Compiler, YUI Compressor
• Added Google Page Speed integration
• Added support for @import processing
• Added controls for page cache purging policy
• Added auto mode for minify (not compatible with CDN)
• Added support for set cookie domain setting
• Added reliability improvements for Amazon Web Services
• Added referrer group management for uniquely caching these cases
• Added Amazon S3 bucket location selection control
• Added support CNAMEs confguration support for Amazon Cloudfront
• Added purge tool
• Added support of custom wp-config.php location
• Added cache busting support
• Improved object caching performance when no plugins are active
• Improved non-blocking JS embedding implementation
• Improved reliability of CDN export operations
• Improved implementation of headers for all cache engines
• Improved minify help (recommendations) tool
• Improved handling of .htaccess directive changes
• Improved support of IIS web server
• Improved varnish support
• Fixed bugs with API changes with Rackspace Cloudfiles
• Fixed bugs with origin push content delivery network methods
• Fixed bug with HTML encoding
• Fixed bug with emptying cache for various cache keys
• Fixed bug with rejected CDN file support
• Fixed bug with HTTPS mode in WP Admin
• Fixed bug with relative document root for disk enhanced page cache
• Fixed bug with trailing slash for disk enhanced page cache
• Fixed bug with minify template group settings being lost upon upgrade
• Fixed division by zero error
• Fixed bug with object cache clones
• Moved browser cache rules to site root instead of document root

Requirements:

• WordPress 3.2 or higher