Flat rate is common in broadband access to the Internet in the USA and many other countries. A charge tariff is a class of linear rate, different from the flat rate, where the user is charged by the uploads and downloads (data transfers).
MUI stands for Multilingual User Interface and .dll.mui files are simply libraries(Dlls) that contain resources dedicated to localization : for an application to support multiple languages,dlls containing specific resources must be available eg language resources(arabic,french,english,chinese....
What is libmmd.dll doing on my computer? The file libmmd.dll is a resource of Adobe Dynamic Link, a feature included in the Adobe Creative Suite that eliminates intermediate rendering between programs. Non-system processes like libmmd.dll originate from software you installed on your system. Since most applications store data in your system's registry, it is likely that over time your registry suffers fragmentation and accumulates invalid entries which can affect your PC's performance.