Ole Eichhorn posted some hypothetical questions regarding what the world would be like if people were larger, richer, more plentiful, smarter by orders of magnitude (unfortunately, I can't seem to find the original post, and he doesn't provide a link in his follow-up). He then posted a follow-up with a concrete poll asking whether we think people will be more or less intelligent in the future.

I voted for less intelligent. I think that the trend of society will be to allow the general populace to get by with using less and less of their inherent intelligence. I feel that, above and beyond people's (possibly) inherent intelligence level, one makes themselves smarter by practicing. I know that the brain isn't really a muscle, but I think the effect is the same: the more you use it, the stronger it becomes. Logic, for example, is a skill that can be learned through use and exercise. Memory can be enhanced through practice. And so forth. The current trend towards increasingly passive forms of entertainment is going to decrease the need and opportunity for people to exercise their active intelligence.

However, I think there is going to be a sub-strata of society that will continue to seek out more active forms of entertainment and learning. These will be the people that eventually will control the majority of the world, creating (because they love to) more technologies that will allow for even greater forms of passive living.

Mary has an interesting spin, saying that the increasing flow and amount of information that is being piped into us will make us smarter. A lot of it boils down to your definition of intelligence. I think that the increasing amount of information won't make us smarter, because we won't really have to remember it, we'll just be more capable (hopefully) of finding out what we are looking for.