A drunk post by Swigg - how cute.
actually drunk boy did a pretty good job of explaining it.
Equity is your "rightful" share of the pot.
In his example above lets say the blinds are .10/.20 villian (with AK) raised to .60, you called from the button, and both blinds folded. There is now $1.50 in the pot.
Based on the pokerstove calculations above you will win this hand 66% of the time so your equity in the pot is 66% of $1.50 or $1.00.
Hope that helps.