distribute the Erlang programs I write to my friends/colleagues/users?
Erlang programs only run on the Erlang VM, so every machine which is going to run an Erlang program needs to have a copy of the Erlang runtime installed. Installing the entire Erlang system from erlang.org (or, perhaps, indirectly via a packaging system such as Debian’s or BSD’s) is the simplest option in many cases. A more modular alternative is to install the CEAN runtime. A further alternative which has fallen into disuse is SAE: stand-alone Erlang. SAE allows an Erlang program to be distributed as just two files, totalling about 500k. SAE no longer works on current Erlang releases, but for historical interest, there is a page about SAE which shows you how to build a self-contained system for the (somewhat outdated) R9B Erlang release.