Talk about being caught between a tweet and a hard place. Twitter, in its infinite wisdom, recently admitted that it messed up and used email addresses and phone numbers — provided by users as part of their account security practices — for advertising purposes.
As Twitter describes:
Tailored Audiences is a version of an industry-standard product that allows advertisers to target ads to customers based on the advertiser’s own marketing lists (e.g., email addresses or phone numbers they have compiled). Partner Audiences allows advertisers to use the same Tailored Audiences features to target ads to audiences provided by third-party partners. When an advertiser uploaded their marketing list, we may have matched people on Twitter to their list based on the email or phone number the Twitter account holder provided for safety and security purposes. This was an error and we apologise.
If you’re annoyed by this, you could always provide Twitter a different email address than the one you regularly use — using something like the ol’ plus sign or period trick in Gmail — or a different phone number, like a Google Voice number. You’ll still be able to take advantage of features like Login Verification, which I urge everyone to turn on, if you forward your texts from your alternate number or otherwise have some other method for receiving them. (You could always stick with the “Mobile security app” option, too.)
Installing a great ad-blocking extension for your browser, or making comprehensive use of Twitter lists on your mobile app, can also help you escape some of the service’s advertising-related annoyances. You can also edit a few settings within Twitter’s Personalisation and data section, if you want to cut down on any attempts to target you based on your identity instead of your raw Twitter activity, and disable various ad-tracking features on your devices.