Here are some interesting sites that I found very useful:

Keen Talks – Watch interesting talks, lectures, debates, presentations and interviews.

Sprword.com – site with a mission to build a brighter future for the entire planet by seeking and spreading truth on a global level, especially with their documentary section.

Motion Empire – this one is my favorite. Well structured, full of content, heaven for documentaries.

OVGuide.com – ultimate video search engine and directory for streaming videos websites. Documentary sites are included.

SnagFilms – the world‘s most compelling documentaries, whether from established heavyweights or first-time filmmakers, available to the wide audience.

PBS Frontline – Credible, thoughtful reporting combined with powerful narrative, a good story well told: That is at the heart of FRONTLINE’s commitment to its viewers.

Documentary Films.NET – valuable resource to those with an interest in documentary films.

Joost – documentaries in high quality resolution.

Box Office Mojo – all time box-office list of documentaries.

HBO Documentary Films – offers a full spectrum of stellar, non-fiction programming by acclaimed documentary filmmakers.

Download Movies – genuinely priced website that offers its users all the latest movies for download, from across different genres.

Reality TV Shows – Download TV Shows from a complete online entertainment resource. Download and Watch all popular TV Shows including action, adventure, animation etc.

TV Downloads – Download TV Shows, latest TV Downloads now in seconds. Subscribe and Download all TV Shows and access TV Downloads and get latest update on TV shows at one click.

Radio Documentaries – Award winning radio documentaries from Ireland – all freely available to listen online or podcast.