SteemFollower and its "Voting Power"

Some of you might have heard about steemfollower website allowing to gain either new follower, either more upvotes by giving upvotes and following.
I searched but didnt find the explanation how "Voting Power" was working.

In fact : each vote will cost 2% of voting power and each user in steemit gets 20% voting power/24hours

Users with more Steem power have an option called 'Voting weight' which can change that 2% cost of each vote for them.

Here is the site : https://steemfollower.com/?r=6441
(with my referral link)