The case of internet communities is widely discussed in the context of the Web 2.0  idea. Cognitive, educational potential of communities is proved in Wikipedia, where groups of users in a dynamic way (discussion, co-operation) build knowledge resources. The quality of theirs works can be sometimes better than articles in the professionals encyclopedias . Despite all the problems connected with collective and freely edited knowledge, Wikipedia became an excellent place for starting a research .
But can online communities be helpful in the case of history preservation? Two projects started some time ago in Poland encourage internet users to collectively gather the historical materials and knowledge.
?ladami Zbrodni  (Traces of the crimes) is a project started by the The Institute of National Remembrance. The main aim of this initiative is to collect information about places and facts connected with little known communist crimes. Pupils, veterans and all the internet users can submit data, which later (after verification) is published on the special page with interactive map . More about this project you can read here .
A very similar project is maintained by the Foundation for the Preservation of Jewish Heritage in Poland. Polin.org.pl  is a web page which collects data about places and objects connected with the polish Jews heritage. It is available in polish and english . Everyone can create his own account on POLIN and add own materials (photos, texts, films). All the submited data is being moderated before publishing it online.
Those projects encourage internet users to take part in the preservation of history. Ken Burst even uses the term „citizen historians“  (like citizen journalists ), describing the possibility of gathering and researching history by non-professionals and using their work for professional educational or research aims. And more, the role of users submitting historical data is a key factor in such projects as September 11 Digital Archive .
The activity of the citizen historians working on the base of institutional projects is one – but not sole – form of historical involvement of online communities. We can ask even if in this polish projects described here there is any community (users can not contact with each other and can not start own initiatives too). Internet historical discussion boards could be a better example of such self-educating and self-researching communities. In the FREHA  community (about historical reenactment movement, 7 960 users) users exchange knowledge and plan collective actions in the topics of historical reenactment. DWS forum  (about the World Wars, 2632 users) or historycy.org  (the largest polish historical internet community, 40 078 users) is also a very active places of historical discussions and collaboration. Maybe such communities (old, active and large) should be more encouraged by institutions to take part in the historical preservation and commemoration projects. Their potential is not noticed too often, unfortunately.