I have been using yahoo messenger for years - its only as safe as your are. Never click on links people send you from nowhere, do not download files people you do not know try to send you. Even if you know the person, never accept a .exe file. Regardless of what program your using, its only as secure as you and your computer. Make sure you have an anti-virus, make sure the security updates are installed,,,,,.
It is safe if you will keep your password in your own. If you share it with others they might open it.
Have you ever disembosomed your password or any other information to others? Take care of your account.
Yes it is absolutely safe, I am using it form past 4-5 years and i haven't come across any such issue yet.
well... I am not Confident on that aspect. I know that there is a tool named yahoo Sniffer that can display you in real time all the IM conversations happening on different computers connected through LAN. If you happen to go to a CyberCafe, and login to Yahoo, there might be someone reading all your IM's.
It is the same as any other chat client on the internet and yahoo being the biggie attracts more hackers etc.