If a consulting client came up to me and asked "Is it better for us to host our own blogging software on our domain inexpertly, get the SEO credit for it, and go down hard for a little while every time we hit social media, or to host on PostTumPressEr with perfect uptime?", I would say "Host yourself!" so fast it would barely be polite.

I don't mean this in an aggressive fashion: your eyeball is worth nothing.

Now, in the real world, hosted blogs do have downtime and self-hosted ones can be made nearly bulletproof by following a few simple guidelines. cough KeepAlive off cough