If you are leaving Twitter, do not deactivate your account. Instead, please set it to private. (If you deactivate it, someone else may be able to claim it in future, and identity squatters are a problem no-one needs.)
@gvwilson
First of all, thank you. It's the right time again to discuss how to #leave a service like Twitter.
I'd strongly prefer to leave your Twitter profile open, though. Here's my reasoning. Past Twitter posts are sometimes not sufficiently bei Web Archives (yet). Findable, referable, potentially useful (you just never know, right?) public knowledge on the web shouldn't go dark. Yes, this is an issue of cultural heritage preservation, nothing less.
Thanks for considering!