User blog comment:ZPPHR/Zane/@comment-203.206.131.170-20121108223520/@comment-5638912-20121108234544

If you haven't notice, each stance has an activation effect. And also, you could stack up to 2 different active effects. For example, Zane activates his Q which will make his ext basic attack do increased overall damage to his target, and passively gaining bonus attack range and magic damage on hit. If you change to his E and haven't attack since you activated Q, your next basic attack w1ll deal 25% increased damage and slow your target, all in one.

I don't know if you have played Udyr or not, but he also doesn't have an actual ability. He, as my Zane, gains bonuses on each stance and an additional effect to his auto-attacks on activation. As well as Udyr, Zane can activate Q, even while on that stance, to proc the active effect again, meaning that you could do 25% more damage every 5 seconds.