Years ago I set up a WordPress blog on my own self-hosted server, based in part on the naive idea that I was going to write enough to make a self-hosted blog worthwhile. This was also back in the day when blogging platforms were limited to either client-side web-page building solutions like iWeb or full CMS systems like WordPress.

In fact, I had begun my little blog experiment using Apple’s fledgling iWeb application and the service then known as .Mac. However, I quickly discovered that solution was untenable for serious content for various reasons, not the least of which was that iWeb 1.0 had a nasty habit of attempting to preserve a WYSIWYG presentation by rendering any non-web-font text as a giant PNG file. After writing a lengthy post on Bluetooth Proximity Detection that received links from several other sites, readers started pointing out to me that they couldn’t copy-and-paste the code snippets I had put in, as the entire article was a single giant image (eek!).

Immediately after discovering that, I migrated the whole thing over to a WordPress installation on my own hosted service. That seemed like a good idea at the time, but the reality is that I never posted as much over there as I expected, and as services such as Tumblr and Posterous came along, I kept thinking it would make a lot more sense to migrate everything over to one of those services instead of maintaining my own WordPress site.

Getting the posts over was never a big concern, particularly as I had to few of them that copy-and-paste remained a viable solution. What kept stopping me was the comments. I didn’t feel right about moving old posts over without also bringing along the relevant comments, and none of the individual blogging platforms offered a migration solution that would fully preserve these with metadata such as their original date and time.

Enter Disqus.

Since Disqus’ entire raison d’être is to host comments and migrate users over from legacy commenting systems, it is obviously an ideal solution for importing comments while leaving the original comment threads and other metadata intact. In fact, migrating a WordPress blog over to use Disqus commenting is almost trivial — install a plug-in, hit an import button, and carry on.

Disqus, however, also has a very robust import and export system to allow comments to be brought in from other services. The only thing required in a Disqus world to attach comments to a given blog post is a URL, meaning that with a bit of simple XML massaging one can easily migrate comments between entirely different blogging platforms, provided both are capable of using Disqus for comments.

In my case, I originally converted my comments on the WordPress blog over to Disqus, however it turns out that this step was unnecessary. Disqus can use a WordPress Extended RSS (WXR) file directly for importing comments into any system, since again all that it really cares about is the URL of a post, not the underlying blog.

Once I had migrated my WordPress posts to Tumblr (which I did manually) all it took to move the comments over from to Tumblr was to export them from WordPress to WXR, change the post URLs in the WXR file to match the Tumblr URLs and then pull that file into my Tumblr-connected Disqus site using Disqus’ import tool. Other than creating the posts in Tumblr so there would be something to attach the comments to, this didn’t even require any work on the Tumblr end, since the comments remain in the Disqus system.

With that, I’ve finally managed to consolidate things into a single system and preserve the comments in the process. I then setup a redirection plug-in over at the old WordPress blog to hand back HTTP 301 redirects to send any traffic over to each specific article on the Tumblr side, ensuring that any links from other sites or Google searches manage to find the articles over here in the new location. Eventually I suspect I can shut down WordPress itself and just redirect the old domain name.