Users can follow other users' blogs. User profiles often have a section dedicated to comments from friends and other users. Developers are able to share applications with all Office users. What about assigning privileges and restricting access to unauthorized users? It was made available for free to all Google Apps for Education users. An estimated 2,860 users have internet access. Internet access itself is limited to a handful of elite users and scientists. Hangouts allows conversations between two or more users. This is due to Microsoft's large market share of desktop computer users. Both faced legal challenges related to content posted by their users. The system generates recommendations using only information about rating profiles for different users or items. Messenger offered file sending capabilities to its users. Controversial features included those some considered useless or too advanced for data processing users. Zip2 allowed for two-way communication between users and advertisers. They were tool users, and makers of tools.