I can't access Facebook just at the moment in order to have a look at the links provided, but generally speaking I think it's a great blessing that monks are able to participate on the Internet.
Obviously, their first obligation comes to the lay community that supports them, but I think it's excellent that if they find spare time, they use this time to support and participate in online communities, be it on Facebook, through maintenance and devleopment of their own websites (ala Bhikkhus Pesala, Samahita, Gavesako etc.) or at forums such as Dhamma Wheel.
I also think their lay supporters would be pleased to know that not only are their offerings helping to support their local Dhamma community, but are also helping to support the growth of the Dhamma more globally.
"Do not force others, including children, by any means whatsoever, to adopt your views, whether by authority, threat, money, propaganda, or even education." - Ven. Thich Nhat Hanh
"Whether I were to preach in brief, Sāriputta, or whether I were to preach in detail, Sāriputta, or whether I were to preach both in brief or in detail, Sāriputta, rare are those who understand." (A I 333, Sāriputtasutta)