How to zoom in with a mouse?
To zoom inside safari you can use 2 fingers pinching in the trackpad.
2 fingers tap will zoom so the text fits the safari window.
Also a single finger double tap in the mighty mouse does the same trick.
(not double click)


If you want even more ways to do stuff with your mouse I know about this software called MagicPrefs that I used for quite some time and loved it.
There is also a similar software called BetterTouchTool.