New metrics: costum variables

I want to add new metrics to the platform, the only way i guess, is with costum variables. Anyone knows another way?

I want to save information about, for example, a click that someone did in a page.

It’s true that we just can track 5 custom variable per visitant?

Right now you can only have 5 variables per visit, we’re going to increase that number at some point though.

What kind of metrics do you want to track?

I want to save actions like the number of positive and negative votes in a topic in a certain page and the number of posts.

Maybe later i want track events like the click and timestamp over a button. Is it possible with piwik?