Although the spread of the “high-choice” Internet brings a great deal of attention to research in partisan-selective exposure, there are not many people choosing media based on their partisanship in reality. On the other hand, preference-based selective exposure, widening gaps in knowledge about political or international news between news seekers and entertainment fans as a result of reducing opportunities for incidental or by-product exposure to news in a high-choice media environment, may become a serious problem in a society made up of less partisan voters. This research focused on this selective exposure and, using an online survey, examined whether online services would widen or narrow voters’ gaps in political knowledge. The results indicate that while exposure to portal sites, newspaper sites, and summary of 2-channel sites decrease in the gap, exposure to news curation applications and Twitter increase in the gap. The implications for possible change in the media environment are discussed.