creating user related user specific content
Do not create a table for each user!  Create a table for each category of information you want to store.

In a relational database, a table typically represents a list of a particular type of thing which is of interest to your system.  This can be a tangible thing, like users, or an intangible thing, like interests.  The point is that each table is about a kind of thing.  The things themselves are rows in a table.  Every row in a table needs to have the same structure.  If you have no consistent structure for your data then you have to consider a No-SQL database instead.

For relational databases, study the rules of database normalization.  This will help you to understand how to structure your database tables.