It is no secret that content is still king, and bloggers know this like no one else. Regularly updated blogs help achieve amazing SEO results in a matter of seconds; and nearly every successful affiliate I know of blogs at least several times a week.

Since WordPress remains to be one of the most popular blogging platforms today — not only among smaller bloggers, but also major news outlets (e.g.: CNN, Forbes, Reuters), Fortune 500 companies (e.g.: GM, UPS, eBay, Sony), and such famous blogs as Mashable and Boing Boing [more here] — I’d like to turn to plugins that help affiliates manage banners in their blogs.

Here are the five that seem to be worth your attention (descriptions taken from what each plugin’s developer provided the WP Plugin Directory with) if you’re looking for an effective way to manage your affiliate banners, as well as AdSense units:

1. Ad Squares Widget — This widget makes it possible for you to display 125×125 ad squares ( or some other configurable size ) into a widget-ready bar for WordPress. You can have just 2 squares, or as many as 8 running together. It also supports multi-widget options. So technically you could have even more than 8 if you add it to a bar more than once. Each ad square accepts any HTML/JavaScript code, so it will work with standard affiliate ads, or even with ad network codes. You can also configure the widget to shuffle the positioning of your squares if you like. The Ad Squares widget supports embedded PHP code too.
2. Random / Rotating Ads V2 — The Datafeedr Random Ads V2 plugin allows you to simply and easily show random, rotating ads anywhere on your site by adding a template tag to your theme’s template files or using widgets.You can show any type of ad: Google Adsense, affiliate ads, banners, images, flash, text, etc… There’s no limit to the number of ads you can put into rotation for an ad spot.
3. Ad Injection — Injects any kind of advert (e.g. Google AdSense, Amazon Associates, ClickBank, TradeDoubler, etc) into the existing content of your WordPress posts and pages. You can control the number of adverts based on the post length, and it can restrict who sees adverts by post age, visitor referrer and IP address. Adverts can be configured in the post (random, top, and bottom positions) or in any widget/sidebar area. There’s support for A:B split testing / ad rotation. And the dynamic restrictions (by IP and referrer) work with WP Super Cache, W3 Total Cache and WP Cache.
4. Adwit Banner Manager — Insert ad spots into your blog and sidebar in one click. You just drag and drop to indicate where you want to place ads on your blog. There is nothing to modify, no HTML knowledge required, no template to edit, nothing to integrate. Everything is done in a minute! It’s that easy. Adwit Banner Manager will place your favorite advertising programs in the right location, without placement errors (wrong ad size, wrong display zone, special template…). Just let the system optimize the ad rotations and find the best random banner to maximize your revenues.
5. Banner Wizz — Gives you the possibility to add contextual banner ads at the beginning or the end of every post of your blog , based on keywords occurrences. Because your blog will have a relevant banner ad on every post ,the plugin will help you maximize your conversions with affiliate programs, products, services or sites you promote on your blog. How does it work? For every banner you add through the admin interface you will need to set some keywords that describe the banner. The plugin counts the keywords in a post and for each post displays the banner with most keywords occurrences. If no keywords are entered, the plugin will act as a banner rotator and it will display a random banner in each post.

If I have missed a plugin which you enjoy using, please do chime in, and mention it through the “Comments” below.

If I were asked which WordPress plugins I would recommend to bloggers that use this popular platform, and want to enhance the usability component, I would list the following five:

1. Akismet [plugin's site] by Matt Mullenweg – Checks comments posted in your blog against their own database and places suspicious ones into a Spam folder. It does a great job, filtering all of the spam in your blog (hence, making it look much cleaner that it would’ve looked without this plugin), as well as makes your job of comment moderation much easier. Keep in mind though that occasionally (as often is the case with email spam filters too) a totally kosher comment may land in that Spam folder. So you want to look through the comments stored in this folder every once in a while (to whitelist the good readers).

2. Subscribe To Comments [plugin's site] by Mark Jaquith – Adds a check box that a commenting reader may tick if they want to be notified of replies to their comment(s). A must have if you want to really engage your audience, which is important not only for your blog’s popularity to grow, but also because some of the most important thoughts and conclusions are born in discussions.

3. WordPress Popular Posts [plugin's site] by Héctor Cabrera – Excellent plugin that sorts your previous blog posts by popularity. Popularity is defined by you. It can either mean “most comments” or “most views”. Regardless of the determinant that you choose, each post can still show both the number of views, and the number of comments (it is all easily customizable). I chose to use this plugin in combination with the Most Popular Posts plugin (which ranks posts by the number of comments one), and have one display posts in order of most views (giving a “Most Viewed Posts” header to this ranking), and the other – by most comments.

4. SexyBookmarks [plugin's site] by Josh Jones and Norman Yung – One really sexy plugin that allows for an array of social bookmarking options to be placed under each of your posts. See it in action right under this post.

5. Seesmic WordPress [plugin's site] by Seesmic Inc – Great plugin for adding video comments (recording them right within your own blog using Seesmic’s platform). Truly adds a new dimension of online communication and brings a blog alive. Even if your readers never use it, use it yourself!

I have arranged the above plugins in order of priority (you can live without video comments, but can’t without filtering those spam comments effectively). I use all of the above.

If I haven’t listed a plugin that in your opinion can greatly improve a WordPress blog’s usability, and enhance user engagement, please write about it in the comments area below. I am open to suggestions, ideas, and always eager to learn from the experience of others.