Permalinks

Linking is a big issue for the web. When the web was originally conceived by Tim Berners Lee, the linking was central to the design. In a way, a relational database was the first real linking engine. (Prior to relational database, databases were heirarchical). However, one of the problems with links using normal web software is that they change when the article is renamed. The permalink, perfected by blogging software, changed this. The format is not standardized across the different blogging software. WordPress uses an automated date structure along with the original post name in order to develop the URL.

http://<site-specific prefix>/<4 digit year>/<2 digit month>/<2 digit day>/<article name>/

However, you also have a selection formats you can use with your permalinks in WordPress

Here you can see the permalink to this post you are reading. 

 

This ULR does not change when the name of the article is changed (although, the option exists).

Tim Berners Lee has written extensively on this subject. 

“It is the the duty of a Webmaster to allocate URIs which you will be able to stand by in 2 years, in 20 years, in 200 years. This needs thought, and organization, and commitment.” – Tim Berners Lee

Tim lists items to leave out of the URI.

• “Authors name- authorship can change with new versions. People quit organizations and hand things on.
• Subject. This is tricky. It always looks good at the time but changes surprisingly fast. I discuss this more below.
• Status- directories like “old” and “draft” and so on, not to mention “latest” and “cool” appear all over file systems. Documents change status – or there would be no point in producing drafts. The latest version of a document needs a persistent identifier whatever its status is. Keep the status out of the name.
• Access. At W3C we divide the site into “Team access”, “Member access” and “Public access”. It sounds good, but of course documents start off as team ideas, are discussed with members, and then go public. A shame indeed if every time some document is opened to wider discussion all the old links to it fail! We are switching to a simple date code now.
• File name extension. This is a very common one. “cgi”, even “.html” is something which will change. You may not be using HTML for that page in 20 years time, but you might want today’s links to it to still be valid. The canonical way of making links to the W3C site doesn’t use the extension.(how?)
• Software mechanisms. Look for “cgi”, “exec” and other give-away “look what software we are using” bits in URIs. Anyone want to commit to using perl cgi scripts all their lives? Nope? Cut out the .pl. Read the server manual on how to do it.
• Disk name – gimme a break! But I’ve seen it.” - http://www.w3.org/Provider/Style/URI

However, many of these best practices have been worked into the naming convention in WordPress. 

Below, is a passage copied from Wikipedia on permalinks. 

“Permalinks frequently consist of a string of characters which represent the date and time of posting, and an identifier which denotes the author who initially authored the item or its subject. Crucially, if an item is changed, renamed, or moved within the internal database, its permalink remains unaltered, as it functions as a magic cookie which references an internal database identifier. If an item is deleted altogether, its permalink can frequently not be reuse” - Wikipedia

Here plasticbag.org discusses the importance of the permalink.

“But why did it take off? What was so important about the permalink? It may seem like a trivial piece of functionality now, but it was effectively the device that turned weblogs from an ease-of-publishing phenomenon into a conversational mess of overlapping communities. For the first time it became relatively easy to gesture directly at a highly specific post on someone else’s site and talk about it. Discussion emerged. Chat emerged. And – as a result – friendships emerged or became more entrenched. The permalink was the first – and most successful – attempt to build bridges between weblogs” – Plasticbag.org http://www.plasticbag.org/archives/2003/06/on_permalinks_and_paradigms/

Domain

One issue related to permalinks is domains. An expired domain can cause the URI to go bad. However, with WordPress, the *****.wordpress.com does not need to be maintained. So you can purchase a domain and assign it to WordPress. However even if the domain expires, the URI continues. This is one advantage to hosting directly with WordPress. 

Related term

Deep linking

http://en.wikipedia.org/wiki/Deep_linking

Tim Berners Lee on URIs

http://www.w3.org/Provider/Style/URI