[silentbicycle]

Newcomers to Erlang tend to do string handling with a heavy Ruby/Java/whatever accent. That's the problem. The default Erlang string type is a linked list of ints (which can be pattern-matched on), but atoms (AKA "symbols" is Lisp, Ruby, etc.) and binaries (arrays of raw binary data) address situations that need more specific trade-offs.

In particular, redundant string concatenation and flattening tends to be CPU hog, but IO-Lists automatically flatten all string types during transmission and have already been thoroughly optimized.

Of course, if you ignore the serialization solutions Erlang provides, there is a performance hit.