Learning about PLN was very interesting. It is something that I'm currently doing in terms of my own professional development I only did not know that it is names PLN. I would include Wikis in my PLN as well as educational blogs. Looking through these two sources provides a wealth of information in terms of foreign language instruction. I also just discovered a very cool website "Academia.edu" this is a website where professionals can upload their research papers to share it with other professionals in their fields. When you sign up you are asked to list your research interests so that the website gets you in touch with other professionals within your field.I'm also following several blogs that a have central focus of teaching Arabic as a second language and these have provided a wealth of information.
I think here the key for effective utilisation for all these wonderful tools is organization and knowing which ones to use and also to not overwhelm yourself with too much tools.