Anyone who uses Facebook or Twitter and doesn't understand the security implications of doing so are either very young, very old, ignorant, or...marketers/advertisers.
Here are a few lines from the article:
In a statement, Twitter said it "cannot say with certainty how many people were impacted", but the BBC understands it affects users globally.
Unusually, the company is not proactively contacting customers directly to inform them of the breach.
The company would not say when it discovered the issue, but said it had addressed the problem “as of September 17” - 21 days ago.