When building a service and having users in the 100's of thousands, what is the most efficient way to store the data? the data im talking about would be things like favorite color or image in the back ground, font they like to use, a company logo, rows sorted a certain way all this data adds up and to my knowledge it would slow down the program? groups and memberships. would it be better to store it in a database or XML file ? or am I missing a new technology that has come out? any ideas would help me dearly so i can stop stressing about this. Thanks guys.