You can bind in-game macros to your mouse buttons, but be careful when using 3rd party "macro" software for your mouse and keyboard. Using these could get you banned.
Gershuun @ Borean Tundra US - Interface & Macros Moderator
It's not macro in quotes, they are Logitech macros.
edit: I can't think of anything at the moment. What would I do? ctrl+shift and then 'b' to use 2 cooldowns at the same time? I can do that with in-game macros already.
For WoW just think of them as extra buttons. They are probably more useful in other games where you respawn and need to press certain button combination to buy a gun and ammo or to cast spells like Counterstrike or Magicka as examples.
Just for the fact that it's against the rules to automate things like that in WoW, the most use you may get out of it is possibly using it to target a Lightwell and Interact with it. It's just not that good to use or supported much in WoW to my knowledge.
Gershuun @ Borean Tundra US - Interface & Macros Moderator