What is Phishing?
Phishing is a scam. The executors of these scams will falsely claim to be from an established, legitimate business, like Adobe, in an attempt to convince you to divulge sensitive personal information such as online account passwords, credit card numbers, or bank account information. The perpetrators are then able to use this private information to access important accounts which could result in identity theft or financial loss.
Phishing can be received in a variety of ways - email, phone call, pop-up, download, etc. - and is engineered to create a false sense of urgency/importance to get you to act quickly and "verify your information".
Adobe strongly recommends that users follow security best practices by exercising caution when opening attachments and links as well as keeping their computers current with the latest patches and updates.