I don't really think that getting an email at dell@domain.com means that a provider's security has been compromised. Not only do you need to use unique email addresses but they should be uncommon. Otherwise it doesn't really do a lot to address the issue. Might I also suggest using subdomains as well.
I disagree. I've been doing this for decades and occasionally I'll get spam/porn to one of the unique addresses I've created. In the past, I would notify the entity of their breach, but they almost never take me seriously so now I just delete their email address.
I've engaged with the breached companies a few times, and when they responded, it turned out in both cases it was actually an email service provider they entrusted with their mailing list that was breached. Companies don't realize how outsourcing can jeopardize their own reputation.
