Staying safe online is important. But a lot of us are making mistakes with the passwords we use for our different accounts. Password manager company Bitwarden found that a quarter of people use the same password for at least 11 sites or apps. And more than one-third of us use personal information in our passwords. Personal information isn't a good idea to use, because it's quite easy for others to find it out. But here's something else that isn't a good idea: using the name of your favorite celebrity, band, singer or superhero! A company called Mailsuite has been looking at the most dangerous pop culture passwords you can use online. Mailsuite made a list of more than 2,600 pop culture terms and almost 64,000 different ways of writing them. It then looked at something called the Pwned Passwords database, which gives information about hundreds of millions of passwords that have been exposed in online data breaches. The pop culture password that came up most was "Superman." It appeared in almost 585,000 data breaches. In second place was the US band Blink-182. Used as a password, it appeared in more than 482,000 data breaches. "Batman," "Star Wars" and "Eminem" were also in the top five. Bitwarden says you should choose a long password that includes letters, numbers and symbols. You should also have a different password for each app you use. Sites like Bitwarden also let you check how strong a password is before you choose it.