[ih] Query: When did the IETF change to "everyone can come"?

[Harald Alvestrand]

Hi,

I'm writing an article on the IETF, where a very small part deals with 
its history.

One thing I'd like to have right in that section:

- The IETF started out as "people who work on DARPA projects related to 
the ARPAnet"
- It continued as "people who work on ARPAnet/Internet connected networks"
- At some point, it changed to "anyone who wants to can come".

Can someone help me by pointing out (with references, if possible) at 
which IETF meetings those changes happened?

Thanks in advance!

                      Harald