could you please give me your opinion whether  PrivateOpps  hyip is a
real good company or a scam..thank you very much

Personal opinion -
No contact information, not a registered company, no information on
the experience of the principals, no regulatory supervision. I could
go on.

"We do have a physical office in San Jose, Costa Rica, which serves as
our headquarters and from which the daily operation is administered.
However, for security reasons and customer privacy concerns, it is not
available for visits at this time."
http://hyip-navigator.com/interview.php?num=39

?PrivateOpps is not a registered entity in any jurisdiction.?
http://www.moneymakergroup.com/index.php?showtopic=18947&st=30

"PrivateOpps Accounts are not insured by any governmental agency or
administered by any banking regulation authority, or subject to any
banking regulations.
PrivateOpps is not registered with the U.S. Securities and Exchange
Commission (SEC), Federal Trade Commission (FTC) or any other
governing body in any jurisdiction."
http://www.privateopps.com/1/terms/

1.4% a day returns?
http://www.privateopps.com/1/contracts/

So my $50 will be worth $7,995 after a year?  Which of the 10 does this sound like?
http://www.dfi.wa.gov/consumers/toptenscams.htm

Any offer suggesting ca. 1% interest per day but requiring a holding
period of 75 days sounds like a Ponti scheme, which is another
expression for a scam.

Run, don't walk, run away from this.  This certainly looks like a scam
or a Ponsi scheme.  (looking at the lowest daily interest rate
"offer") It is possible to make money trading Foreign exchange,
however, this usually means a highly leveraged position with a lot of
risk. (eg Futures markets, options etc.)  Also I don't see where the
fees for the offerer are to benefit from.  Certainly, these people
aren't doing it for free.  What are they getting out of this?  (World
peace?)

The way these people make money off the greed of others.  Don't do it.