normalize is different. it's mostly about avoid duplicated info.
at any rate you could very well have comma in your text, it's just that if you pass inline user input inline in your queries this will cause problem, i.e:
var uName = "lloyd, "<br />
...<br />
var sql = "select * from user where name like '" + uNname + "'";
which you solve by NEVER having inline user input, instead use SQL query parameter
var cmd = new SqlCommand("select * from user where name like $user");<br />
cmd.Parameters.Add("user", "lloyd, ");