No problem, I'll just go down the list and answer.

• how voting tokens are giving to people accounts (for instance if someone have 100SP or 10,000SP, what's the diffrence)
  • Your tokens are just worth different amounts, you'd still get the same amount. Tokens would be meant to act as a limit to your number of votes (in a visible way), but they would still be proportional to your steem power. 1 token from someone with 100 SP will be worth less then 1 token from someone with 100,000 SP, just like current voting.
• how long are they still useful (1 month, 1 year ?). Could they accumulate ?
  • I think they're useful forever, in the proposed situation I put forth you'd only be able to have 350 of them at any given time (7 days worth). So you can't build up months worth of tokens, only 7 days.
• if someone register with multiple fake accounts, does he gets voting tokens for each one ?
  • Yes, but since they're proportional to the SP of the accounts, it's no different than the current system. 10 accounts right now with 100 SP each would have the same voting power as 10 accounts with voting tokens and 100 SP.
• if voting tokens are given in a few quantity, isn't ther a great risk that they are used only for limited users or limited posts, concnetrating more than now the posts rewards ?
  • If you missed it, 0.14.0 has some proposals in it that would be doing this anyways, except in a more restrictive fashion. This proposal has some of the same risks of concentration because of fewer votes, but would give people a bit more clarify on how they could be used best.
• what about curation rewards ? are they same as now ?
  • Yep, same as they are right now. Using 10x tokens (10% weight each) would be the exact same in curation rewards as a single 100% vote at 100% voting power.