Social networking is becoming more and more popular. In keeping with the trend, I have started tweeting on Twitter, with updates on the Americans for UNESCO blogs. Twitter is a microblog, with entries limited to 140 characters. You can read the postings you are following via your computer or your cell phone. The Americans for UNESCO entries are found under the username AmUNESCO.
Jennie Lawrence has also created a Twitter account with the username UNESCOoer, which focuses on UNESCO's Open Education Resources.
LinkedIn, the social networking site I use most because it serves a community strongly involved in international development, has a UNESCO Group. Currently there are 141 member who can hold discussions, share news, advertise jobs, etc.
There are other LinkedIn groups related to UNESCO, such as the International Webmasters Group, but most are smaller and linked to rather specific fields.
Facebook, a social networking site very popular with youths and the general population has a Group focusing on World Heritage Sites, as well as one for Friends of World Heritage.