With Robert Scoble joining fast company, Techcrunch has reported that the scobleizer blog, long with out ads, just a plug for his book will be redesigned, and start taking ads. One of the last major big A List bloggers pressured or as Techcrunch suggests sold out because of the job move.
Unfortunately, this is not a new thing, any person who takes a job has to sign a large amount of paper, some of that paper will state that the company owns/controls and can use anything you design, create or develop while at that company. If Robert signed such paper, and he just blindly signed them, then yes, the Scoble web site is no longer his, and anything he writes, blogs, televises, thinks about is now owned by Fast Company. Intellectual property rights, invention rights, companies want those.
Companies will hand you paper that you will sign that they own everything that you create. The distinction between use of work computers, off or on hours (tell that to someone on call), all that will be decided in the courts. If there is even a hint that you used company resources to blog, invent, or do schoolwork, it all belongs to the company.
It might not be so much a matter of selling out; it might be pressure from the company, big wads of cash, an easily recognizable name, popularity, and a way to capitalize on the Robert Scoble name for Fast Company. The web site is just part of the whole package, one with an already inbuilt readership that will not go away because Fast Company slapped some ads on it.
The problem will come in, how many ads, and will they get in the way of the rather austere and simple blog that is already in place?

If you work, and if you blog, create, invent, make sure you alter that simple little paragraph so that you retain control over the media, design, invention that you create. Never ever, use a work computer for anything other than work, and follow up regularly to make sure that the company is OK with what you are doing.
People forget what you altered in your agree to work for them papers, managers, people change, and it is always good to follow up. We did our follow up with the company to make sure that they are aware, cool with, and understand, ended up better than we thought. There are cool companies out there, you just need to make sure you work for one that understands all about new media, what it is, how it works, and the neat things you can do with it.