Email about Social number on the dark web but when I check turbo tax there are no details

To clarify, this is not from Turbotax, but from IDNotify, which is a service you might subscribe to as an add-on when filing your return.    For more specific details, you would have to log into IDNotify.

After the most recent breaches, I think everyone pretty much needs to assume their information is available.  the real problem is that SSNs are not supposed to be used for identification but they have become so more or less by accident.

You can pay for credit monitoring but that is probably more than most people need to do.  I have placed either a lock or a freeze on my credit files (prevents most attempts to take out new loans in my name) and I have credit cards that provide credit monitoring -- they will tell me if my score decreases and I can go look why that might be.  You want to make sure you use secure passwords on your banking sites and don't re-use passwords--if someone cracks a low security site like a fan web site you comment on, you don't want that password to also work on high security sites like banks and investments.  You can also turn on two-factor authentication when available.