do you have to tape cement board before tiling?
Yes you need to tape the cement board just like drywall to avoid cracking problems later on. If you're gonna do a job, do it right.
you dont have to but the idea is to fill and fiberglass tape the seams keeping them ridged so that in years to come the grout doesnt crack out. Yet thats something rather new, you should be fine just filling any of the voids with mastic adhesive as you lay them. A portland cement mix works well on durarock, and the new backer board, though drywall quickset works just as well.
