Reposting from ebil_trio:
All e-mails and password combinations from mangatraders have been leaked and are accesible online (nearly a million I think).
If you used your mangatrader e-mail and password combination on any important sites (PayPal, Ebay and such) make sure to change it there now.
Also change the password on your e-mail account immidiately if you used the same password on mangatrader.
If someone is able to access your e-mail account they are able to acces most sites that you registered on using that e-mail account.
If you aren't sure if you have a mangatrader account: If you downloaded anything at any point from their site you had an account since it's neccessary to have one to be able to download from there.
Here's a list that someone made (this one is without the passwords because I don't want to spread the one with passwords),it's not complete I think so don't feel safe if your Email is not on it. (It's huge and takes time to load)
Additional info (since some people seem a little confused on what this leak means):
This is not about changing your info on mangatraders (they are down anyways and the information is already out on the internet). This is about changing your passwords on other sites in case you used the same email/pw combo that you used on mangatraders on those other sites. People will try to enter your e-mail and your password on PayPal and other sites to see if they manage to get in, they will also try the password on the e-mail account you used and try to access that one.
tl;dr
If you have used the email/pw combo that you used on mangatraders on any other sites that are important then go change the password there now!