If you don't live in the US or Israel, the settlement doesn't apply to you. If the email came from anyone but Yahoo themselves, it is either an agency looking to take a cut of any potential settlement, or far more likely a scam looking to encourage you to give them your personal details.
No one is getting big money from this, in most cases they'll just pay a credit monitoring service on your behalf. See here for more.
Oh - I didnt click through any links - and when doing a google search there was a number of sites discussing this item. I dont expect to get any cash and I know Class Settlements dont apply outside of the USA. Just seemed avery interesting mail.