Allow us to leave!
Here's one yardstick that I use before signing up for any new online service: I first search the Interwebs for stories from users who tried to close their account and to leave same service, and were given a hard time. I understand that commercially it is "rewarding" to show 300 million subscribers, even if 90% of them are stale accounts. But from a privacy and data security point of view, it does NOT make any sense for a user to leave an account behind that he/she knows for sure will never be used again. Some services, also larger ones, are handling this issue professionally, and have a decently findable link on their home page that allows the closing of an account and deletion of stored data. Others .. give you the run-around via six levels of customer "service", and in the end, they basically change your username to username.inactive, but leave everything else as-is. And keep spamming you, too.
If you have stories to share about online services that don't let you leave, please do so below. Keep it PG-13 and factual, please, but if a little ire shines through, we understand ...