Weddingbee boards

Mrs. Corn - I'm pretty sure those are the ones that are one long piece, with a detachable RSVP card - and you just fold them up, address the outside, seal with a sticker, and pop them in the mail.  No envelope.  That type is all one piece. 

There are also some with multiple parts, where the envelopment serves as the envelope - I haven't seen those called seal-and-sends, and I'm with litsecretary in wondering if they would make it through the machines without being damaged and maybe torn open, particularly if you're using a petal-fold type.

Jeninvra - I would think that whether they are appropriate would depend on the kind of wedding you are having.  It's an ecologically correct but kind of informal looking invitation.  If you're expecting your guests to wear black tie, maybe go with a more formal style in 100% cotton or paper made of recycled materials.  If you're having a pretty informal celebration, why not use them?  I actually ordered a couple of samples of seal-and-sends, but both my FI and my mom hated them with a passion, and then I was lured to the dark side by the fabulous sparkly pocketfolds.  I think if you like the seal-and-sends, and your family is a little more open-minded than mine, you should go for it.

Actually I guess I should clarify - mom and FI hated the first kind.  The second kind they thought were okay, but also thought we would need to order envelopes for them.  Kind of defeats the purpose, I think, but solves the potential problem of them coming open in the mail.  Although the samples I ordered of the second kind the pocketfold was pretty stout; I'm not sure it would come apart in the mail.