When to use permalinks and trackbacks? This has been my question before and most likely to be the question of most as well. First, what are trackbacks?
Here’s a useful definition according to wikipedia:
TrackBack is a mechanism for the communication between blogs: if a blogger writes a new entry commenting on, or referring to, an entry found at another blog, and both blogging tools support the TrackBack protocol, then the commenting blogger can notify the other blog with a “TrackBack ping“; the receiving blog will typically display summaries of, and links to, all the commenting entries below the original entry. This allows for conversations spanning several blogs that readers can easily follow.
Blogging software that supports the TrackBack protocol displays a “TrackBack URL” along with every entry. This URL is used by the commenting blogger, whose software will send XML-formatted information about the new entry to this URL. Some blogging tools are able to discover these TrackBack URLs automatically, others require the commenting blogger to enter them manually.
The TrackBack specification is due to Six Apart who first implemented it in their Movable Type blogging software in 2002. It has since been implemented in most other blogging tools. Six Apart started a working group in February 2006 to improve the Trackback protocol and have it potentially approved as an internet standard by the IETF. One notable blogging tool that does not support trackback yet is Blogger.
Some individuals or companies have abused the TrackBack feature to insert spam links on some blogs (see sping). This is similar to comment spam but avoids some of the safeguards designed to stop the latter practice. As a result, TrackBack spam filters similar to those implemented against comment spam now exist in many weblog publishing systems. Many blogs have stopped using trackbacks because dealing with spam became too burdensome.
Aside from trackbacks, there is also what we call a pingback which can also be found in wikipedia. Essentially, pingbacks and trackbacks are the same.
So when do we use trackbacks? With the advent of modern day blogging tools such as Wordpress, the issue is actually no longer an issue 
since wordpress automatically automatically detects the trackback URL if there is any on the page that you link to.
Here’s another URL that might help though it’s for MovableType. But it does show the “sense” in using trackbacks.
Lastly, in wordpress, you can force pinging of trackback URLs by entering them in the “Trackbacks” field when you write a new post. The trackbacks field can be usually found below the “editor” when posting.
Hope this helps!
Hi,
I have multiple users in one of the blogs I maintain. I want to be able to list all users in the homepage, and when they click on the name, the posts are filtered according to the user name.
Is this possible?
Thanks.
Greg
[...] A couple of weeks ago, I was so excited to see that I had a lot of ‘comments’ for moderation only to find out that they’re all spam – all 43 of them! I then thought, how could comment spam go through if I have the captcha plugin installed? At first, I thought the spammers were deliberately typing in their spam into my blog but when I checked, all the ‘comments’ were actually trackback spam! Now I know how it got through captcha. For those who don’t know, captcha is a wordpress comment plugin that adds a set of characters to type in a small graphic before someone can post a comment. [...]