Many years ago I used Posterous as my blog, in good HN fashion.

Aaaaand it went away.

Walled gardens are always going to be a massive vulnerability for link rot.

This time with Medium will be different! /s

Although I couldn't see a way to do it when I first looked at Medium, I'm told that there is now a way to use it with your own URLs.

I haven't bothered to examine how it works, but if you can do that and you have a disaster recovery plan that replicates your entire output to a different service (e.g. GitHub Pages) while retaining the link structure, then perhaps Medium is now superior to Posterous's original offering.

There used to be a way. The user had to fill a form and pay (less than 100usd, IIRC) and they would set up a custom domain for you.

The last time I googled it they had it discontinued this option.

Self-host - or at least use a platform that you can easily migrate away from without breaking urls.

Cool URIs don't change and all that... Thank heavens for the Internet Archive.

Twitter is not exactly a walled garden, though. AFAIK it's perfectly indexable.

Doesn't Twitter gate high volume access behind contracts for money?

In any case, if Twitter allows posy deletion, then it's standard. You may consider deleting bad form, but that's just another case of someone's perception of a platform not matching reality.

The internet makes it hard to definitively remove something, but a large percentage has already been lost to churn and bit rot due to lack of care.

If you think this will upset future historians, just wait until you find out that this is something that journalists like to do with their Twitter accounts too, and I would be entirely unsurprised if there's an overlap between the journalists who do this and the ones that start dubious but widely believed viral claims using their Twitter accounts.