:I think the article is quite useful. In general I've found detailed historical background of immense value in my programming careerit's always helpful to understand why various decisions were made and the thinking processes involved, and "those who forget the past are condemned to repeat it". But Allan's point is also valid, it's not an article one would find in a traditional encyclopedia. Is this a bad thing? 

 :I don't believe so. Many of the limitations found in traditional encyclopedias were for economic or practical reasons, not because the information wouldn't be useful; Wikipedia doesn't share these concerns, and this sort of thing is a large part of what could make Wikipedia a superior product. But I'm not the arbiter for what goes in Wikipedia, and I claim complete ignorance of Wikipedia style in general. 

 :I'm in favor of this level of detail, but it definitely should be kept separate from main articles. Speaking as a user I prefer to see small overview articles which link to more specific articles on subtopics. That way I don't have to read it, but it's there for me to peruse as needed or at my leisure. 

 :The recent changes to Actor model were very positive. I might suggest going even further and moving more of the text (example: "Models prior to the Actor model" and "Message Passing Semantics") to other article(s) as appropriate. If I'm looking for a quick overview of the Actor model I'm much more likely to be interested in "Why is the Actor model important now?" than those other two sectionstoo much detail, even though it's useful and interesting in its own right.