It was an acrylic dispersion. We used less filler to get more tack - or changed to a different grade. (we bought the polymer in so we couldn't make changes to it really). You could also add some coalescing solvent, but this is digressing really.
If you used polyvinyl alcohol you would get a more traditional glue, but it wont be water proof when set. With the emulsion it takes longer to dry and is less tacky to start, so you may have to clamp the joint on place as it dries, but you'll get a stronger final bond and it will be waterproof.
Basically it was just like "No more nails" - a tough, waterbased general building adhesive. The bond when the stuff is dry is very strong.