I started this blog in 2004. Since that time, there have been a lot of changes in writing and publishing your own online content.
To give a bit of perspective, back in January 2004, WordPress had only (by a matter of days) hit 1.0, and still wasn't really a thing yet. Back then, it was really only Blogger (newly acquired by Google), or older services like LiveJournal that allowed you to have a blog. To give even more perspective, even MySpace wasn't really a thing yet.
So, in the 16 years that I have maintained this blog, I have seen a lot of services come and (some) go in that time. For a non-exhaustive list: Blogger, MySpace, Facebook, Twitter, Tumblr, WordPress.com, Medium, Instagram, amongst others.
Throughout each iteration, people have always asked me: "why do you manage and host your own blog when you can just use [insert one of the above services] like everyone else seems to be doing?"
Throughout all that time, I have always owned and hosted my own blog (of course, via a hosting provider). The point is that I control my platform. Although I currently host my own WordPress install, previously I hosted a custom blog script. While I understand that this isn't practical for most people, it is important to me.
My reasons for hosting my own blog on a platform managed by me:
Customisation of my content
For better or worse, I like to be able to control the look of my site, down to the finest detail. This is mostly not possible on other services, or at least not as customisable.
Control of the presentation of my content
If you've used Facebook or Twitter to post content, you know that how they present what and where is almost a dark art. I like how I present and structure my content, so a blogging platform is a necessity.
Ever tried to view a simple chronological list of stuff you've done on a social media platform? Have you noticed how they sometimes 'choose' what to show you and what to leave out? Yeah nah, I don't like that.
Ownership of my content
This is especially important to me. My content (i.e. what I write and the pictures I post etc.) are my own property. Although on 'reputable' sites like Facebook, you still 'own' your content, this isn't always the case, and the waters are very muddy in this regard. Although you might own it, you are hardly in control of it. Which leads me to...
Control of what my content is used for
It's (now) no secret that Facebook, Google, and most other free (or even paid!) online services use what you give them to make money. This is usually to serve you targeted advertising, or to sell information on you to third party companies.
I don't want the act of producing content for this blog to be used like that against me, and for as much as I can reasonably control, I do not knowingly do any of this for any of my visitors. Although I use services that might be a little opaque on what they collect—for example, I use Akismet to stop comment spam, use some selected features of the WordPress Jetpack plugin, and have a Twitter widget in the right sidebar—I don't make any money off anyone visiting this site. (Slight disclaimer: I did experiment with Google Ads for the briefest time in 2006, and made a whopping USD$0.48.)
I've even stopped using Google Analytics on this site because I became uncomfortable with how they might be tracking me and my visitors.
Almost all these things you can't control on other services, and most of the time you don't even know they are doing it.
For all the above reasons, I still go to the effort of paying for and hosting my own blog. In the beginning it was the only way of doing it, but now I choose to even though it's not the most convenient or easiest option.