It is unfortunate in this day and age that as much as the internet has progressed, it is still exceedingly difficult to actually close, a.k.a. delete an account for almost any given web service.
Why is it so difficult to close accounts? Because the way most user databases are designed simply don’t allow it. If you’re user #492862, your account can’t be truly deleted because then the whole database would be "off by one" and mess up everyone else’s accounts. What happens instead is that your account is simply "hidden" if you elect to close it.
In other words, it’s impractical to even think about actually deleting any account you have out there, because there’s basically no way to do it. Even if a web service states your account is deleted, it isn’t. Just moved and hidden. That being the case, you are better off modifying the existing account and then abandoning it entirely.
How to abandon any web account
Step 1. Use a standalone password manager
I use KeePass for all my accounts. For you Linux folk out there, you would use KeePassX. Both are free. For security reasons it’s much better to use either one as it’s a standalone program that is not integrated into the browser. Personally – and I know this is overkill – I consider saving passwords in a browser to be a not-so smart maneuver because a) Most spyware/malware exploits are specifically designed for web browsers, b) You figuratively paint yourself in a corner by having all password management in a single browser (and I’m sorry but the ones that say they work across multiple browsers usually work poorly at best), and c) You have far superior password management control in a standalone password manager client.
KeePass or KeePassX act just like a file manager. It’s easy to move things around, manage your account data easier, create folders, import/export data easily and so on.
The best feature however is one that’s not even listed – and that’s the ability to create an "Abandoned" folder. When you abandon an account, you should not delete the information you have on it, but rather just move it to your "Abandoned" password manager folder. I’ll talk about that more in a moment.
Start by putting all your accounts into a password manager. This may take time. Possibly several hours. But it’s worth it.
Step 2. Modify the web account you want to abandon and change all pertinent information.
For whatever web account you’re setting up to abandon, you modify it specifically to point to throw-away information. For the email address, point that to a throw-away (you probably already have one just for that purpose). For accounts that requires a phone number, get a Google Voice number and point to that (especially helpful if the account doesn’t allow the change of a phone number without verifying it first with a call or text message).
Step 3. Once the changes are completed and the account updated with the new information, move the entry in your password manager to your "Abandoned" folder.
It’s becoming increasingly common that businesses simply never delete accounts, and things can and do screw up on their end. For an account you abandoned five years ago (only because you had no real way of deleting it), that company may have been bought and sold three times by now, reactivated the account accidentally due to data fumbling on their part, and well, you can see how that would be a problem for you. If on the other hand you took the steps to modify the account and point it to throw-away information, if a company screws up and starts doing wacky things with old accounts you abandoned a long time ago, it doesn’t affect you at all and that’s good peace of mind right there.
Password managers are small and the account data held within them is just encrypted text and nothing more, so there is no reason to permanently delete anything out of there. After modifying any account you plan to abandon, simply move it to your designated "Abandoned" folder and that’s all there is to it.
What do I mean by "web account"?
Any account that requires a username and password to use it.
For example, got an old MySpace account? Put it in the password manager, change the email address to a throw-away, then move the password manager entry to the Abandoned folder.
Whatever is out there that you signed up for, gather all that account data in your password manager, modify appropriately and move to Abandoned so you have better control over all of it.
If the web service offers an option to "close" or "delete" an account, should you do it?
You can, but I’d still keep the old information in the password manager Abandoned folder anyway. If you elect to do that, I’d suggest putting a note in the title of the entry in your password manager, such as "MySpace – closed 14-May-2012". This lets you know exactly when you closed the account just in case you ever needed the information. For entries such as closed financial accounts, that’s especially good information to have just in case you ever need it.