Hungarian notation is no longer needed to identify data types like in your string example, but it still can be useful for identifying characteristics of variables in other ways. Here's a good article that talks about useful ways of using the Hungarian notation: http://www.joelonsoftware.com/articles/Wrong.html
Here's an excerpt
"In Simonyi’s version of Hungarian notation, every variable was prefixed with a lower case tag that indicated the kind of thing that the variable contained.
For example, if the variable name is rwCol, rw is the prefix.
I’m using the word kind on purpose, there, because Simonyi mistakenly used the word type in his paper, and generations of programmers misunderstood what he meant."
He also uses an example of identifying strings prefixed with an 's' or a 'u' to identify if they are secure to print out or not, so that a statement like print(uSomeString); can easily be identified as wrong.