When looking at US tablet ownership and usage by age group, Jumptap found that those ages 25 to 34 led the pack. Almost one-quarter of those in this group owned a tablet, while about one in five said they had made a purchase on one of the devices. Interestingly, those ages 18 to 34 favored iPads, while those ages 45 to 64 were much more likely to own a Kindle Fire. Advertisers looking to target specific age groups should keep these preferences in mind when determining their ad buys. Read the rest at eMarketer.