This screenshot below is from their FAQ:
I think they lied.
How does Hyves take care of your privacy?
To protect your privacy, you can determine for each section of your profile whether it is visible to nobody, friends, friends of friends, Hyvers, or everybody. I think that’s a good system. The same options are available for “who can search the Hyves site and find me by my surname”. This really is a good thing. If you set that to “Hyvers”, it enables you to be found by old school friends who already have a Hyves account, while not attracting any attention from outsiders. Even if the rest of your profile is closed for anybody but friends, at least people will be able to contact you via the site to ask for your approval to become friends on Hyves.
So, what’s the problem then?
The problem is, that Hyves decided to change the rules. Per 30 January, they will let Google find Hyves members by their surname. Including all the people who had set their preferences to let only Hyvers find them by their surname. Several members have expressed their concern in comments on Hyves HQ blog, but the answer remains the same: “we can’t please everyone, and you can opt-out if you like, so there is no problem”. The repeated requests to make it an opt-in instead of opt-out and to give one single good reason why it is opt-out instead of opt-in, are simply ignored or rebutted with “we don’t see the problem”.
This isn’t all though. They also have not officially informed their members of this fact. It was mentioned in the blog of Hyves’ PR man Raymond Spanjar, but while that post was briefly featured on the Hyves homepage, it is now only linked in the sidebar, hiding inconspicuously between other non-important links. Most Hyves’ members aren’t even aware that 30 January will see their Hyves profile linked to their surname in Google, even if they had specifically set “only findable by Hyvers”.
Bad form Hyves, very bad form.