One of the most magical things about WordPress is also one of its most frustrating. As explained here, WordPress Shortcodes “let you do nifty things with very little effort”. It’s a great description. WordPress has a bunch of shortcodes built right in.
But WordPress shortcodes can also be added to your web site, and there are several ways to make that happen. You could write your own code or pay someone to do that for you. Your theme might include WordPress shortcodes that either do special things or make things look special. Or you could add a group of shortcodes to your site by adding a plug-in with one or a collection of WordPress shortcodes.
There are advantages to each of the techniques. Writing your own, though not generally necessary or especially cost effective, puts the least strain on your site’s performance. Having shortcodes built into your WordPress theme is great as long as you have codes that do what you need, but becomes a problem if you ever switch themes. And adding shortcodes to WordPress via WordPress Shortcodes plug-ins adds bloat, but is portable; change themes and your WordPress shortcodes will continue to function (and perhaps even more importantly won’t look bad as in the example we described in this post on WordPress Hosting and Backup).
WPSquared recently published a not-nearly-comprehensive roundup of WordPress Shortcodes Plug-ins. If you’d like to explore the plug-ins model for shortcodes, it’s a pretty good place to start. And if you feel like you need to understand the idea a bit better, you can Get WordPress Help from The WordPress Helpers.