Someone has been using my Gmail address to sign me up for things online, and I consistently get explicit emails sent to my inbox and my spam box. I have decided to get a new email address, abandon my current one and delete it from my phone account. What will happen to my old email address when I’m not using it? IMB

It’s amazing how little progress we have made in the past 30-odd years. First, any company that still emails people – or adds them to mailing lists – without a “double opt-in” is run by idiots. If anyone signs up for anything, they should get an email that they must click to confirm they really want whatever it is. This remains true even for porn sites.

Second, Google has no problem censoring pornography in its search results, even if you turn SafeSearch off. However, it is apparently beyond its ability to provide an opt-in SafeSearch setting for email. Are ordinary users expected to construct their own email filter with the right keywords to divert pornographic emails to the Spam bucket, or delete them all together?

I’ve been using Gmail for 15 years – it celebrated its birthday on 1 April – and it has managed to put some remarkable emails in my Spam box. These include confirmation of my appointment at the London Passport Office, an editorial commission from the Guardian, a file shared by a colleague, and dozens of press releases and newsletters. How does Gmail’s spam filtering block, for example, a news release about research at the University of Sheffield, from my inbox while letting porn sail through into yours?

Canning spam

Having said that, you need to help. For example, if you access Gmail from a browser, you can choose a set of pornographic emails and select the option under More to “Filter messages like these”. In the smartphone app, you can select several porn emails, tap the three dots in the top right and select “Report spam”. (Technically, emails that “you” supposedly requested are not spam, but we’re just trying to retrain Google’s AI.)

Next, turn images off. It’s hard to stop idiots from spamming you, but you don’t have to look at their images.

Using Google’s “priority inbox” should also help. This tells Google to pre-sort incoming emails into separate sections, such as Social, Promotions, Updates and Forums. If your porn-spam is moved into Promotions then it won’t be in your primary mail feed.

In a browser, click the cogwheel for Settings, select “Configure Inbox” and tick all the options. In the Android app, tap the hamburger menu (three horizontal lines) and then scroll down to Settings, near the end. Finally, select “Inbox type” and choose “Priority Inbox”. The instructions for iPhones and iPads are in the adjacent tab.

If you can tame the porn spam, you might be able to salvage your email address.

Whitelisting

The tragedy of email is that most of us have no interest in around 75%-97% of the emails we receive. If that’s the case, you may as well tell Gmail to put everything in the Spam folder, and whitelist the 3% or so that we actually want.

It is probably easiest to do this in the web interface.

Click the cogwheel icon and select Settings, then click “Filters and blocked addresses”. If you decide to create a new filter, putting your own email address in the “To” field should catch most things.

What happens next?

If you abandon your mailbox, it will keep working, perhaps for some time. Eventually, however, incoming email will eat up the 15GB of storage space that Gmail shares with some other files in Google Drive. Once that happens, Google will start sending you serious warnings about the lack of space, and might even suggest you buy a bit more.

Eventually, however, Gmail will refuse to send or receive any more emails. Incoming emails will be bounced, and the sender will get a message that says something like “Your email could not be delivered because the account you are trying to reach has exceeded its storage quota.”

At this point, you could still rescue your mailbox by logging on with a browser, running some searches to find and delete hundreds of unwanted emails, and then emptying the bin to recover the space. Eventually, however, Google will delete the account. This will mean that neither you nor anyone else can use that email address again. That is sad news for the thousands of people who have common names: if you missed it at the beginning, it’s gone forever.

Google doesn’t seem to delete mailboxes quickly. It has said it could delete mailboxes after nine months, not that it would. I’ve seen at least one survive for several years.

Google also has an Inactive Account Manager, which lets you pass on your data (from Gmail, Blogger, YouTube and so on) to a trusted person after a specified amount of time. This could be important if you get knocked down by a bus …

Services tied to email addresses

Abandoning or deleting an account sounds like an easy way out, but in many cases, it could be catastrophic. Your email address may identify you to dozens or even hundreds of websites and services.

In Google’s case, your emails, G-Suite and Gdrive files, Google Photos, Calendar, to-do lists and Play data will all disappear, along with your Chrome bookmarks and any apps, music, movies, books and games you have paid for.

Further, Facebook and Instagram, your bank, your local council, your doctor and other essential services may all know you by your Gmail address.

Of course, you can go to Google Take-out and download all your data, then go through all your websites and services and replace the old email address with a new one. If you’re lucky, you won’t have a lot to do, or to lose. For others, it will be a world of pain. I don’t recommend it.

Have you got a question? Email it to Ask.Jack@theguardian.com