Now as a developer primarily working in Ruby, I always feel the need to have a side project to hack on in addition to my day job. The side projects allow for unsafe experimentation with new technologies. After a reasonable amount of vetting, I find that I'm able to make better decisions in my day job as a result. I think most Ruby developers today work in a similar fashion.
The startups that I've worked for never had much concern about what I did in my personal time, but now that I'm working for an acquired company that's part of a big corporate entity, it's a little different. I get more of the looks, comments, etc and can't be as public about my side projects. Also I can't take the side projects as seriously (i.e. get paid subscribers) because that could jeopardize my employment. I'm okay with this for now, but I understand that many would find this appalling. I think you just have to find the right balance between what's good for you versus what's good for them.