Amazon’s Twitch unit said its website for streaming videogame play was likely hacked, though in disclosing the possible compromise the company raised more questions than it answered.

Twitch said in emails to those potentially affected that their password, email address, user name, home address, phone number and date of birth may have been accessed. Twitch canceled the password of those who received the email, noting the passwords are encrypted but still could have been accessed. It also cut off access to YouTube and Twitter...