Broken links are a significant problem for all websites because they negatively affect both SEO and the user experience. This plugin monitors internal links, external links and images in templates, posts, pages, comments, the blogroll and, optionally, custom fields, and then alerts admin when it finds broken items.
Another must-have, this WP plugin automatically generates Google +1 buttons for all posts, and it works for single pages as well as loops.
In its default configuration, WP is a solid SEO platform, but there is room for improvement. This plugin is that upgrade; it helps authors write better content, and includes an array of technical optimizations. Top features include advanced meta and link control, better social integration, breadcrumbs and RSS optimization.
This plugin provides valuable SEO benefits by automatically linking keywords and keyword phrases to other posts, pages, categories and tags on a WP site.
Word Stats is an amazing linguistics suite for webmasters who track keyword usage. The plugin provides advanced statistics for all assigned keywords and keyword phrases. It also monitors readability, and has an excellent goal system.
This excellent plugin significantly upgrades the built-in WordPress security. It blocks harmful queries, hides backend-dashboard and wp-version, and removes all exposed sensitive data, including error and update information.
ManageWP is a necessary tool for all webmasters who manage multiple WP sites. This plugin lets the user manage them all from a single dashboard, and that dashboard is even available remotely. ManageWP is very fast and highly secure, and it provides most features in one-click fashion.
The community is the lifeblood of any blog. Disqus is a service and tool that makes the WP comment system easier, more powerful and more interactive. It includes a powerful API, and allows multiple WP sites to join a unified discussion community.
After the Deadline is an awesome WP tool usable by both site admin and site visitors that uses advanced algorithms to check spelling, style and grammar, similar to Microsoft Office. This plugin is free, and much more advanced than the default WordPress spellchecking system.
This plugin allows visitors to view a mobile version of the site. It works well on nearly all PDAs, smartphones and tablets, and it is particularly well optimized for Android and iOS devices.
This plugin lets the author flag a post as a review. Review posts allow visitors to rate the posts based on a series of aspects, and after voting, it displays the combined results. The webmaster can set up review profiles, or can dictate a unique configuration for any post.
Akismet is an invaluable weapon in the battle against blog spam. This anti-spam tool automatically examines blog comments against the Akismet web service, and then sends admin notifications for the items flagged likely to be spam.
Page slugs are the WordPress-generated URLs for posts. Often, slugs contain words that have no SEO value, so this plugin ensures that all page slugs are lean and mean for SEO purposes.
There are certain times when it’s necessary to block user access to a WP site, such as when upgrading the WP installation or changing the theme. This plugin makes that process simple by adding a maintenance mode that handles the minutiae and politely informs visitors.
Images have no inherent SEO value, which is why it’s crucial to add proper ALT and TITLE attributes. This plugin makes that simpler by auto-generating valid tags based on the filename.
Created by the WordPress SEO developers, this tool is by far the most powerful and intuitive Google Analytics plugin for WP. In addition to providing excellent tracking tools, it ensures that Google is recording the proper data for that site.
Ad Injection is the most powerful free ad injector suite on the market. It injects ads and content into posts and widgets, and out of the box, it supports a wide array of ad networks, including Google AdSense and Amazon Associates.
Search Meter is an extremely useful plugin that tracks what readers are searching for on a blog. Webmasters can use this information to determine the type of content that they should add to the site.
This plugin allows web authors to publish tweets, re-tweets, replies, direct messages and so forth. It supports multiple Twitter accounts, and it offers extensive control, so webmasters can show, hide, include and exclude on a per-item basis.
This plugin allows developers to easily create and edit contact forms for all WordPress pages. This is a better alternative to direct e-mailing, and the system provides excellent integration with the Akismet anti-spam platform.
A related posts feature provides two benefits: It guides the reader, keeping them on the site, and the internal links have a lot of SEO value. This related posts feature is similar to the one used on the New York Times website.
This plugin is similar to a related posts feature, but rather than display similar posts, it displays recent and popular posts from within the entire category. This plugin works well as a complement to SimpleReach Slide or other related posts plugins.
Category pages are a popular WP feature, but there are two limitations: They contain only links and no real content, which is not optimal for SEO, and there’s no control over which articles show first. This plugin removes those limitations by letting admin sticky entire posts at the top of category pages.
This WP plugin takes the burden out of managing 301 redirections and 404 errors. It manages them, monitors them, tidies them and sends notifications when it requires human assistance.
This WP plugin is a sophisticated and heavily automated sitemap solution. WordPress SEO, which is the best SEO-oriented WP plugin, does include a sitemap feature, but this plugin is a strong option for developers who need more features and more control.
Flexo is the ultimate all-in-one Facebook manager for a WordPress website. It integrates directly into the site in templates, posts, pages, categories and widgets. It also boasts a wide range of options, and it has many social networking optimization tools and features.
The only thing Flexo doesn’t do is add a like box to your WP site, and like boxes are particularly effective tools for blog authors who interact heavily with the community. This plugin adds the like box, and provides a wide range of options for positioning, colors, borders, field adjustments and so forth.
This plugin allows site admin to communicate via email with visitors that comment on the site. This is a great tool for authors who interact with the community often, and it lets the author communicate right from the comment that inspired them to do so.
TubePress is a simple plugin that lets webmasters integrate YouTube and Vimeo videos and galleries into their WP sites easily. Advanced features include auto-hide controls and sequential auto-play.
AuthorSure adds a wide range of features, including Google Authorship Verification, Google Plus integration, and the connection of posts, archives and author pages using rel=author, rel=me and rel=publisher. This plugin has much value for all WP sites, but it’s particularly valuable to those that have guest bloggers who want inline credit.
WP-DB-Backup is a plugin that lets the user back up core WP data tables by default, and the user can configure it to back up any other tables in the same database. Regular back up of the databases is vital, and this is by far the best free option available.
WordPress pings each time a post is created, including during edits, and this leads to the notorious problem where harmless but heavily edited WP sites are flagged as ping spammers. This plugin overcomes that problem through a smart pinging approach.
Super Cache effectively reduces load on any web server. By default, a server must process a WP page each time it’s loaded. This plugin creates HTML files that do not require that processing, and that makes everything run faster and smoother.
If a permalink is about to generate a 404, this plugin intercedes, and searches for a similar slug. If it finds one, it creates a 301 Moved Permanently error, and then it forwards the user. This plugin is particularly useful for sites that have moved to a new permalink structure, or sites that change permalinks often.
Feedburner is an excellent free service for bloggers that gathers a variety of useful information about feed subscribers. This plugin makes it easy to use Feedburner with WordPress, and it automatically redirects RSS feeds to the Feedburner account.
This plugin adds a broad set of powerful search and replace functions, and administrators can use this to search and replace nearly any type of data stored on the site. It boasts the full power of PHP regular expressions, and it’s a particularly useful tool during site migration.
For some blogs, Akismet alone is not enough, so this plugin adds an anti-spam mechanism to the comments section and other aspects of the website, and sites can require CAPTCHA for all users or just the anonymous ones. Re-CAPTCHA is particularly popular because, as a side benefit, it assists Google’s OCR project.
Changing the default account name is another way to secure a WP installation. It’s just another hurdle for would-be hackers to overcome. Unfortunately, WordPress doesn’t allow this, but this plugin does.
This plugin provides an additional level of security by monitoring files, and then notifying the webmaster by e-mail whenever changes are detected. The plugin can monitor by hash and timestamp, and it can exclude files, directories and changes made by approved accounts.
Cart66 Lite is an excellent e-commerce solution for small enterprises. It supports services, physical products and digital products, and it handles orders, shipping, taxes and even promotions. If the site eventually requires a pro solution, Cart66 Lite easily transitions to Cart66 Pro.
Often, webmasters will need to reorder pages, and this can be a very clumsy and tedious process. This plugin simplifies it by allowing the ordering of pages through a drag-and-drop interface. The plugin also includes a widget the better exposes the options found in the wp_list_pages function.
WP-Paginate is a pagination plugin that is powerful and intuitive. It provides visitors with easier navigation and a better overall experience, and it has a positive effect on SEO.
This WP plugin is an excellent diagnostic tool for slow WP sites. Generally, slowness is caused by poorly performing SQL queries. This plugin examines all queries on the frontend, and identifies the slowest ones.
This plugin automatically replaces standard dates on articles/posts with phrases, such as freshly baked, yesterday, last week, last month, a year ago, and a long time ago. The webmasters can edit the phrases and time ranges.
PhotoDropper is a useful content creation plugin that lets a post author easily drag and drop Creative Commons licensed images into their posts.
The original TinyMCE WYSIWYG editor plugin was so good that the WP developers integrated it into the default configuration. TinyMCE Advanced replaces the default editor seamlessly, and it adds a wide array of additional features.