In earlier post I referenced a Pew survey that suggested the impact of excluding cell phones from telephone samples has a negligible effect on estimates, at least for now. But I've just seen an interesting post on FiveThirtyEight.com that would seem to call that into question. They have arrayed the Obama margin of all of the major polls on this chart below.
The yellow bars indicate polls that include cell phones and the story would seem to fit with what we would expect,namely, that the younger demographic that generally favors Obama gets under represented when cell phones are excluded from the sample. One poll not in the list that many have pointed to in recent days as evidence that things are tightening is Maxon Dixon and it, too, excludes cell phones.
It's going to be very interesting to see how all of this gets worked out once the real poll (a.k.a. election) results are in.