Open-ness in adoption is a tricky subject, and I see it on a continuum of "very open" to "definitely closed". Truthfully, I think most people involved in domestic infant adoption are in the "as open as possible" end of the spectrum, while people involved in foster care adoption are more frequently in the "very closed" end of the spectrum (with individual variations that depend on specific circumstances).
It's because of Eli that I see the desire of an adoptee to have relationships with birth family members to come to terms with and understand adoption. In Eli's case, I definitely wish we could have more openness. We are able to communicate with his former foster family occasionally through email, but that's it. He's not spoken a lot about it, but there have already been a few times where he's wondered aloud about his birthparents. It's times like that I wish I could sit down and email them, and ask certain questions for him.
It's because of Itty Bitty that I can definitely sympathize with birth family members who deeply love a child who was has been adopted and want to know how he/she is doing. In Itty Bitty's case, we've been fairly open with certain people involved in his case, though we don't have any contact with his birth parents. We are hoping and praying that IF we do not get the opportunity to adopt him (we are still waiting, and will likely be waiting until late August, at least), that his relatives will be open and communicative with us, as we have with them. We love him dearly, and if he ends up leaving our home, we will desperately want to know how he's doing as he grows up. And as he grows up, we will want him to know us and be able to ask questions about his babyhood.
It's because of some of the other children who have been in our home that I understand that birth family contact ISN'T always in the best interests of a child. This is why proponents of "open adoption in every case" get on my nerves. In foster care adoption, when a child has been hurt/neglected by a birth parent to the point that reunification isn't possible, contact is often detrimental. Sometimes, ongoing contact with a family member can work out well - but not always. In this case, adoptive parents need to carefully consider what is in the CHILD'S best interests. And that's going to vary wildly from case to case - and it may change as the years go by.
I have also learned that openness only works if all parties are willing to work together. I've actually really struggled with - and at one point, resented - the amount of openness in some of my foster kids' cases; I've had two cases where the level of openness is too high. I've been very angry with birthparents who insist on lying repeatedly to their children or who openly (and unapologetically) disrespect me. Having repeated contact with a birth parent who doesn't care about the needs of his/her own child is what I've had the hardest time with as a foster parent, and it really does make me want to shut down lines of communication. It also helps me sympathize (somewhat) with families who seek a "closed" adoption with no contact between birth and adoptive families.