Is that possible to use other streamyx account?

Yes. Indeed.

For example, if your streamyx account is only basic 512K, but you got no money to upgrade to 1Mbps to watch youtube without buffering, therefore you can try out this trick how to hack other people streamyx account and use at your own place.

Disclaimer: Use this trick at your own risk !!

before year 2009, most of the streamyx customer was given default password as tmnet123. Therefore using this exploit, we can easily get the others streamyx account, all we need to do is try our luck to get the streamyx account username.

Please go to https://tmbill.tm.net.my/SelfCare/Maintenance/selfcareLogin.jsp to enter the username and password. If error as above appear, that means you might enter the wrong username or password. Try another account  instead.

Once you enter the correct password and username, the message as picture above will shown. That's mean the account can be use at your own place d ! However we can only check out the internet speed only when we are successfully connect using the username and password.

Once you get the correct password and username, just log in to your modem/router and modify the connection setting. Each router may have different configuration, please refer to the respective user manual of your router/modem. Here we are using the free modem given by the streamyx as example.

If you wondering when you are using other people's streamyx account, will the people disconnected or their internet speed will be slowed down? The answer is they won't be disconnected because their account can be logged in by many users at the same time. Yes, their internet speed will be slow down, because you are using his account and thus you are sharing speed with him, so please behave yourself, DO NOT open ppstream when you are using other's people account because ppstream can eat up the 90% speed!!! Imagine u are stealing his account and you are greedy use up the 90% speed for the ppstream, his got 10% internet speed only, he pay RM88 every month to get 10% speed only? do you feel guilty? Haha.  - quoted from http://ye5.blogspot.com/2010/12/hack-streamyx-account.html

But the question is how can you get many username to test it out?
The answer is simple. Use google to get it !!
Try search on the google using this string  - "contact us intext:@streamyx.com", and you can possibly get million of streamyx account username. =)