You should explain the information that you are gathering and why you are collecting the data. Emails and cookies are very common information to track, so there are a lot of great examples out there. If you are gathering information for any sketchy reasons, you should stop these practices instead of trying to explain it to your visitors.
The important information that you should include is if you are sharing information with anyone. This is a huge part because you need to inform the users where their information is going. In most areas, you do not need to list the exact company, but you do have state clearly that the information gathered is being shared or sold.
You should also have information about the laws and initiatives that you are complying with. Having this information is legally required in some areas, and you can face fines if this information is missing.
Depending on the information that you are collecting and what it is being used for, you should include information about how the users can opt out. Most email collections will have this information at the bottom of every e-mail, and somewhere on the host website.
Who is the site/app owner?
What data is being collected? How is that data being collected?
For which purposes is the data collected? Analytics? Email Marketing?
What third parties will have access to the information? Will any third party collect data through widgets (e.g. social buttons) and integrations (e.g. Facebook connect)?
What rights do users have? Can they request to see the data you have on them, can they request to rectify, erase or block their data (under European regulations most of this is mandatory)?