In the few years I've been working as a software engineer, I have had the chance to be a part of different types of companies; From the small startup in the creative space, to the more corporate large-ish public facing .com company.
I remember a few months into working at the small startup, I told everyone that I was applying for a job in consulting. They happily offer to write me a letter of recommendation, despite the little value it might have had since the company was just starting out. In the end, I stayed there for 2 years before I feel it was really the time for me to move on.
Another job was not as supportive; I had the idea of starting a public facing blog for the development team. The response was rather cold, ‘what good could it bring? first, we potentially will share knowledge to competitors, and second, other company might steal our smartest devs!’. This tells so much about the company's vision towards personal development. ‘Keep them from growing [externally], otherwise people will leave!’
This view is definitely not shared across the industry. Take Twitter, PlanCast, Klout as an example. The dev teams are helping each other out to overcome technical challenges. Or companies like Facebook who open sourced most of their underlying technologies. Or even companies like Microsoft which promoted the use of public blogs, podcasts, videos to share knowledge.
Call me naive, but I feel those days when employees work 40 years with only one company are over. Employment is now about sharing mutual respect, growing together and potentially :at some point- moving on to the next bigger better things.
I truly believe in these day and age, any one company could only be a part of one's career for so far. There's going to be a time where the employee will outgrow (or be outgrown) by the company. At that point in time, he/ she will find themselves in a position where they will bring so much more value to a different company.
Good companies, however, will grow organically with the employees. These companies understand that the only way for them to be successful is to grow their people both from an internal career ladder and external; encouraging their people to bring impact to the public, gaining the community respect and reputation in the process.
Companies have to remember that to be great, one has to be surrounded by other great people.
NB: the picture above is showing my employer is highlighting one of my personal web venture on their news page.