information mod? how does it callled

[Amit86]

when i surfed in a few forums and websites i saw something like this:

The Internet bla bla blabla bla blabla bla blabla bla blabla bla blabla bla blabla bla bla

when you hover the "Internet" text it gives you an explanation about the text, can we do this in vB?
what does this mod called if so?