The most user-friendly app for blocking access to social networking services is Net Nanny. This intuitive program allows users to monitor and manage their children's internet usage in order to protect them from potentially harmful content. With its customizable filters, parents can quickly block websites, restrict searches, and even pause the internet connection if necessary. Additionally, Net Nanny can also be used to identify potential online predators or cyberbullies, and alert parents if something suspicious is happening. In short, Net Nanny is an effective and user-friendly way to keep kids safe online.