I think participating in a PLN is great for educators since we are collaborators. Diigo is also a great way to keep track of sites you visit often and can then access them anywhere as opposed to just on your school computer. I joined Diigo because it’s easy to use and it keeps your sites/blogs organized for you. I am visiting/following 3 sites: Edutopia.com, Funbrain.com, and apple.com
As far as commenting, it is very important to practice online courtesy and of course you want people to visit your blog so you have to do things such as post questions or links so that others will be interested in what you have to share and continue to visit your blog. I don’t mind sharing my thoughts publicly via a blog or web site. I prefer this much more than standing in front of a group and saying the same things. My team is a small group so I don’t see a difference between posting and sharing with them in person. Larger groups are a different issue.