Is that site that connects genetic siblings from same donor sperm a good thing to use if curious?

Yes, if UR curious. You have nothing to lose and may gain a half sibling. Good luck.
Genetic Sibs, Donor. The question may be better phrased as: "do genetic siblings from donor sperm want to know each other, on is it better to preserve anonynmity?" these type of "siblings" would be half-sibs, and may not even know that they are the product of donor sperm, so i would suggest very careful use of information like this, and discourage it.