On the net there are many sites that allow listen to music for free, just doing that search in Google I find myself in the first positions with one who, in addition to offering music, requests the user and password from the MSN to recommend the web:
According to them it is easy, safe and fast … the first and third are true, but sure? I do not think so.
The place does not offer security and with the information they get will be able do anything, from storing it to selling it, to using it to send spam and even chat messages to all contacts. I'm not saying that they actually do these things, but the script they use to validate the login is the same one used by all the clones of the one who admits you and none have a good background.
The site seems to be very popular and as a webmaster I don't see the need to dirty it that way, but hey, what I'm interested in highlighting is the usual. There is no need to enter passwords on sites other than the original ones, especially if it is for a service such as email. If you do, it is best to change them as soon as possible to avoid surprises.
See also: Spam in the messenger with nutritional products.