Thanks David! This is a valuable and informative input. I am more comfortable talking about technical stuff, but the social part of the things is probably as important, if not more. If I were to summarize what you said with my words, that would be that one can observe positive energy flowing off one project and into another. One doesn't necessarily need to know or explain the reasons, but it is reasonable to be where the positive energy is.
I am considering proposing my small library into Boost, and I also feel a bit uncomfortable. First, it is my understanding that I need to come "prepared". That is, have done the research, have a repo, docs, tests, answers to many questions. That is ok, I guess. I don't think you need to go that far if you're just testing the waters with a "would something like this be useful in Boost?" sort of question. But by the time you're asking for a formal review then yes, you need to come prepared, as much as anything to make the reviewers job as easy as possible - ideally just grab the source from git, read the docs, build a few examples and be good to go. The thing I fear most is that I would have to integrate my library with the Boost infrastructure. It may be just perception, but the subprojects, b2 stuff is above my level. I know that I would receive help. But still, the amount of the perceived complexity puts me off.
That's the easy bit ;) No honestly it is, and you would get a lot of help there I'm sure. For the purposes of a review any level of integration isn't really required - although it would certainly make life easier if your library followed the same general directory structure as Boost. I'm not even sure if we would demand b2 build support these days, as long as we can clearly see there is some good quality CI going on.
It is likely that I myself might also have exposed this ungrateful attitude. If I have anything in my defense it is that I often cannot see a good initiative if it is not sufficiently advertised or visible. When a new library is added, I can see that. When infrastructure is improved, I am likely to miss it.
I think there is a lot more going on than people realize, and much of it is hidden away from view on github. A Boost team blog anyone? John.