(updated Thu 16.9.2010)
I have experience with both types of blogging, the free range one, like on this blog, where I can say or do whatever I like, but may only reach a limited audience, and the institutionalised blog, where I get some extra traffic courtesy of the hosting organisation and the other bloggers, but have to use the platform as it is provided by the organisation, and my content should probably also conform with the expectations of the hosting body.
In science blogging, in particular, I often come across such institutionalised "battery blogs" (eg the nature networks, and just now the Guardian has also started a network of science blogs), but I'm rarely tempted to follow any of them. Nothing against the people writing there, but if I see a platform where 30 people are blogging about science, I couldn't possibly make the time to follow them all, and so I take the shortcut of following none and sticking with my eclectic list of "wild bloggers" that I have accumulated over the years.
Also, in my understanding the whole point of blogs is that they are independent of the established media outlets, so if major newspaper or magazine publishers launch blog platforms, I am getting suspicious that they want to hark back the control they fear to lose.
Another reason why I prefer the wild ones is that the institutionalised ones are dominated by male writers - I always had this impression, now Jenny Rohn has collected data confirming it.
Am I the only one who feels that anarchic urge not to let blogging be locked up in cages ? All opinions welcome.