Yahoo Messenger 11.5 is an adware. Adware means that the Yahoo Messenger 11.5 would generate an advertisement or sponsored banner/link automatically in to the client applications / software. For some reason such as if you using a limited bandwidth for your internet connections, cutting unnecessary bandwidth would save a lot. This means for Yahoo Messenger 11.5, disabling the Advertisement on its, stop the bandwidth usage for loading the banner or ads link.
Ad Banner Remover Lite Review for Yahoo Messenger 11.5
Blocking or disabling ads on Yahoo Messenger 11.5 can be obtained by several ways. The tricky ways that almost works in all version of Yahoo Messenger is tweaking the windows hosts file (for Windows OS Only) or tricking the registry. But you can do the simple way by using Ad Banner Remover Applications.