I also received the email. I was leery as it came to an old email that I usually only receive spam on these days. I went to snopes.com: Urban Legends Reference Pages (also known as the urban legend website) to check out the legitimacy of the email. This site checks out all sorts of things and determine the validity of whatever they are researching. They found the email to be legit and showed a sample of the exact email I received. I haven't signed up, yet. I am still debating.

I got life lock.

I have also read this is a legit offer from Target however my question is how did they obtain my email address as I did not use a Target card (nor have I ever had one) during the time their system was compromised???
Anyone have that answer....please post. Thank you.

We did go to our local bank immediately after hearing about this and have had both cards that were used there replaced with new ones. The clerks had been inundated with customers doing the same.

The credit card I used has been replaced by the issuer. They had contacted me about the issue then sent new cards. Keep checking your accounts every couple days.

I made my purchase online and so they had my email address for confirmation. Wondered that myself until I recalled the online purchase.

Thanks for your reply.
I've never ordered anything from Target online and the email address they used to notify me about signing up for the ID protection is not one on file with our bank card used at Target.
Still a mystery to me.