Can I delete my Skype account?

If it wasn't thought about when the software was designed then it can cause very nasty issues and be hard to rectify.

One of the forums I run on vBulletin has over 4m posts, 2m private messages, 45k users.

vBulletin is MySQL and tries to reduce database load through denormalisation of the data. The posts table has the username repeated every time a post was made, and the private message table has a horrible PHP serialized array containing the username in the "To:" column for a private message.

Changing a username on vBulletin involves an UPDATE statement on the post table, which is fine... but it involves iterating through every private message, de-serialising the To information, modifying and putting back.

And vBulletin is MySQL, and the search is full_text, which means MyISAM tables, and the update of the private message table locks for the duration, and for a large number of private messages the table is locked for 15 minutes on that particular server... which is enough time to cause a domino effect of query waits that PHP runs out of memory and one by one my frontend servers fail and the site goes offline.

Yup, vBulletin will crash and take the site offline if you have a large number of private messages and want to change a username.

You can see the fun of explaining this to the users of one forum over here: https://www.lfgss.com/thread95475.html

This is one of the very many annoyances that has led me to create http://microco.sm/ to fix this (and many other) pain points for admins and users. The software design is stopping users doing things they want to do (change their username).

HN isn't running vBulletin. But the logic is much the same. If it wasn't thought about on day one the data structures likely do not permit an efficient changing of username.

HN is under substantially more load than the forums I run, and dang likely deals with far more performance related issues. I'm sure he can reveal HNs specific design flaw that prevents username changes.

Or perhaps it's just the idea that it's a social problem and that if patio11 changed to patm that it would break the context for all previous mentions of him. Again... software should have solved this, but only if it was thought about early enough. The lack of avatars does mean that the username on HN is a far more critical identifier.

It's more likely that the revenue earned by the service is heavily dependent on building a social profile. A properly deleted (without a trace) account reduces the profile accuracy. I also wouldn't rule out the almost too obvious government surveillance requirement.

Just in case an unexperienced developer reads that. Don't do it. If you expect high read loads, better invest your time in learning/thinking about caching, fragment caching, russian doll caching and invalidating these caches. Memcached or Redis come to my mind.

Total control?

Does the person who made this submission have the right to delete it even though by doing so they delete your data?

Do other users have the right to delete your data?

Total control for you means denying someone else the right to delete this conversation.

Do other users have the right to redefine your data by changing the context surrounding it?

If you posted "I vote for this too" to some very sound proposal to allow changing of usernames, and then the original author changed the proposal to "Bestiality should be legal", thus suggesting to the world you support such a thing... did the other user have right through the control of their data to substantial modify the context of your data? To the point that the other person could create a personal liability for you?

Where do the lines start and end, if your content can stand alone then the issues are not there. Almost everything in a forum is a discussion, conversation, argument, debate, an interaction depending on the context of other people's content. The minutes of those things are a record of fact, that someone said something and someone else replied and said something else. Content on a forum is never detached from the content of others.

I agree you have the right to your data, but disagree someone has the right to modify those minutes, those records of fact, to impact the data of other people in any way.

A forum is a collective work, and the rules for a collective work are different to the rules of a personal work.