Each entry in the blog is called a post. Every post usually has a number of different parts. Of course, the two most obvious parts are title and content. The content is text, images, links, and so on. Posts can even contain multimedia. Every post also has a publication timestamp, and most also have one or more categories, tags, comments, and so on. It is these posts, or entries, that are displayed in a reverse chronological order on the main page of the blog. The latest post is displayed first in order to give the viewer the latest news on the subject.

Categories and tags are ways to organize and find posts within a blog and even across blogs. Categories are like topics, whereas tags are more like keywords. For example, for a blog about food and cooking, there might be a category called Recipes, but every post in that category would have different tags (for example, soup, baked, vegetarian, dairy-free, and so on).

Most blogs allow visitors to post comments about the posts. This gives readers the opportunity to interact with the writer of the blog, thus making the whole enterprise interactive. Often, the writer of the blog will respond to comments by posting comments, which makes for a continuous public online conversation or dialogue.

A blog has dozens or hundreds of posts, each of which has a unique ID, and so, many blog engines provide a way to link directly to each post. A permalink is a nicely-formatted link that usually has some form of the post title in the link. For example, a post with the title Everything You Wanted To Know About Eggplant might have the permalink http://myblog.com/everything-you-wanted-to-know-about-eggplant. Permalinks are often more search-engine-friendly, especially if the blogger keeps search engines in mind when creating titles.

Permalinks is WordPress's fancy word for what used to be called SEO-friendly URLs. SEO stands for Search Engine Optimization because sensible URLs, like permalinks, are easier for search engines (such as Google and Yahoo) to catalog. These days, they are often known as pretty or user-friendly URLs. These URLs tell a story about the page they represent, and don't have a lot of confusing punctuations in them. For example, if you are looking at a blog archive for the month of April 2008 in WordPress, the regular URL would look like this: http://yoursite.com/index.php?m=200804. If you enable permalinks, the URL will look like this instead: http://yoursite.com/2008/04/post_title/. An even bigger contrast shows up if you're looking at pages. Let's say you have a page with information about you, the author of your blog. The regular URL would look like this: http://yoursite.com/index.php?page_id=23. If you enable permalinks, the URL will look like this: http://yoursite.com/about.

The theme for a blog is the design and layout that you choose for your blog. In most blogs, the content (for example, posts) is separate from the visual layout. This means you can change the visual layout of your blog at any time without having to worry about the content being affected.

RSS is an acronym for Really Simple Syndication, and Chapter 7 addresses the topic of feeds in detail. For now, understand that RSS and feeds are a way to syndicate the content of your blog so that people can subscribe to it. This means people do not actually have to visit your blog regularly to see what you've added. They can subscribe and have new content delivered to them via email or through a feed reader.

It's important to understand the difference between a page and a post. Unlike posts, pages do not depend on having timestamps and are not displayed in chronological order. They also do not have categories or tags. A page is a piece of content with only a title and content (an example would be About Me or Contact Us). It is likely that the number of pages on your site remains relatively static, whereas new posts are added every day or so. Thus pages have static content, while posts have dynamic content.

In web years, WordPress has been around for quite a while and was in development the whole time, getting better constantly. WordPress's very first release, Version 0.70, was released in May 2003. Since then, it has had nine major releases, with a number of minor ones in between. Each release came with more features and better security.

WordPress is a constantly evolving application. It's never left alone to stagnate. The developers are working continually to keep it ahead of spammers and hackers, and also to evolve the application based on the evolving needs of its users.

WordPress is not being developed by a lonely programmer in a dark basement room. On the contrary, there is a large community of people working on it by developing, troubleshooting, making suggestions, and testing the application. With such a large group of people involved, the application is most likely to have continued well-being.

In addition to having an extremely strong core, WordPress is also quite extendable. This means that once you get started with it, the possibilities are nearly limitless. Any additional functionality that you can dream of can be added by way of a plugin that you or your programmer friends can write.

Here is a detailed list of many features of WordPress:

As WordPress is always actively developed, it's important to keep yourself up-to-date with the software community about their latest activities. The most important spot to visit or subscribe to is WordPress Releases: http://wordpress.org/development/category/releases/. Whenever there is a new release—be it a major release, or an interim bug fix, or an upgrade—it will be here.

The WordPress Codex is the central repository of all the information the official WordPress team has published to help people work with WordPress.

The Codex has some basic tutorials for getting started with WordPress such as a detailed step-by-step discussion of installation, lists of every template tag and hook, and a lot more. Throughout this book, I'll be providing links to specific pages within the Codex, which will provide more or advanced information on the topics in this book.

There are official directories for themes and for plugins on wordpress.org. Though not every theme and plugin is available here, the ones that are here have been vetted by the community to some extent. Anything you download from these directories is likely to be relatively bug-free. You can also see what the community thinks of these downloads by looking at ratings, comments, and popularity.

Additionally, plugins in the Plugin Directory are automatically upgradable from within your WordPress Administration Panel, whereas other plugins have to be upgraded manually.

Theme Directory: http://wordpress.org/extend/themes/

Plugin Directory: http://wordpress.org/extend/plugins/

You'll notice that all of the URLs above belong to wordpress.org. There is another website, wordpress.com, which is actually a free blog-hosting service. Anyone can open an account on WordPress.com and instantly have his or her own WordPress-driven blog. According to WordPress.com, there were over 6 million blogs on WordPress.com and over 9 million active installations of the WordPress.org software as of December 2008.

In Chapter 2, we will discuss all of the differences between having your blog on WordPress.com versus downloading the software from wordpress.org and hosting it yourself, but the basic difference is the level of control. If your blog is on WordPress.com, you have less control over plugins, themes, and other details of the blog because everything is managed and made worry-free by the WordPress.com service.