The move to Github is interesting. I'm wondering if this is harbinger of Codeplex's doom very soon.
I wouldn't read too much into that though - huge company, a bunch of projects and different audiences. CodePlex has an audience - there's a bunch of cool projects on there, too.
It is, however, the only repo under the "Microsoft" GitHub user AFAICT (https://github.com/Microsoft).
This means I can make a lateral (stack) move without having to revert back to "junior" status. Hey, I love me some C# and .NET but the offers from the open-source community are just too tempting.
I booked an interview.
Early web technologies like CGI, PHP, JSP, ColdFusion, ASP and ASP.NET arose due to real-world needs.
Ruby on Rails, on the other hand, arose mainly due to hype.
From a technological perspective, there really wasn't anything special about Ruby on Rails. Many of us who had been doing web development for some time had already built or used proprietary/in-house frameworks that offered the same functionality, but were written in Perl, Python or Tcl instead.
If it weren't for strong and very loud personalities within the Ruby on Rails community, combined with some very lucky timing with respect to the rise of the so-called "Web 2.0", it likely wouldn't have been seen as "special", and wouldn't have garnered the hype that it did.
Technologies that come out of an environment of hype, rather than solving real problems, tend not to stick around as long. Systems built using technologies that solve real problems continue to be used and maintained. Systems built using technology chosen purely because some manager or executive saw a webcast full of nice-sounding buzzwords tend not to survive very long.
I remember Pythonistas at the time raised similar complaints about how Python already had all this stuff — but the thing is, Rails did a nice job of packaging it up in a way that was easy for disaffected Java jockeys to get into and start having fun, while the Python approach at the time was more along the lines of "take this thing and that thing — or maybe one of these five other things, we can't decide — then make this other piece yourself and stick them together with chewing gum."
Rails did come to prominence largely through social channels rather than technical superiority, but it wasn't a marketing-driven hype train targeted at nontechnical managers — it appealed to hackers who wanted to have fun but did not already have a homebrew Perl stack at the ready.
That's how I remember it, anyway.
I've made several stack switches without issue. Usually it involves switching languages at your current company, then using your current salary as leverage to get the next.
The main barrier is HR, which you can get around using this method.