According to Amazon’s “Bestsellers in Electronics” list, the company’s $114 ad-subsidized “Kindle with Special Offers,” is the most popular model in the Kindle family of eReaders. The device — launched on April 13th — is just $25 cheaper than the $139 Kindle Wi-Fi version, but it comes with sponsored screen savers and advertisements on the bottom of the screen. We originally suspected that most people would splurge for the Wi-Fi version and avoid ads, but perhaps users ...