Space News:

NASA - Astronomy Picture of the Day
"Sky and Telescope" magazine. Free articles.

Sites of Other Amateurs:

Noel Carboni
Chris Cook
Ivan Eder
Robert Gendler
Dietmar Hager (in German)
Tony Hallas
Gerald Hitz
Michal Kaluzny (in Polish)
Yuuji Kitahara
Dave Kodama
Walter Koprolin
Thierry Legault
Jerry Lodriguss
Steve Mazlin
Axel Mellinger
Kunihiko Okano
Philip Perkins
Michael Posavec
Philipp Salzgeber
Gerard Therin (in French)
Chris Vedeler

Sites of Organizations (amateur + professional):

Astronomical Society of New South Wales (AU)
Astronomische Gesellschaft (DE)
Canberra Astronomical Society (AU)
Linzer Astronomische Gemeinschaft (AT)
National Aeronautics and Space Administration (US)
Royal Astronomical Society of Canada (CA)
Vereinigung der Sternfreunde e.V. (DE)

Special concern:

International Dark-Sky Association
A Strong Light Pollution Awareness Video

Sites of Observatories (amateur + professional):

Australian Astronomical Observatory [f.k.a. "Anglo-Australian Telescope"] (AU)
Sternwarte Hochbärneck (AT)
Instituto de Astrofísica de Canarias (ES)
Kuffner Sternwarte (AT)
Misti Mountain Observatory (US)
Mount Wilson observatory (US)
Sternwarte Gahberg (AT)
Vatican Observatory (VA)

Remarkable Instruments:

The Most Expensive & Amazing Telescopes In History
25 Public Showcase Observatories in the USA

Astronomy and History:

Top Astronomy Nasa Photos Of All Time

Famous Persons:

In memory to Robert Burnham jr.
In memory to Hermann Mucke (in German)

Astronomy Basics, Education, Libraries, References:

Kids and Education:

The reasons why we explore the sky
A collection of articles addressing questions kids ask about astronomy
Let's play outer space! Games with astronomy background
A parents' guide to foster their kids' interest in astronomy

Intro's:

A beginner's guide for the cost-contious astronomer from the UK perspective
An astronomy guide for beginners by Derek Hales: Techniques and equipment
An appetizer to astronomy with plenty of references to astronomical content
Astronomy related page containing references grouped by target groups
A flashlight on how data science fuels modern astronomy

Fun and Mind-Blows:

Let's play astronomy! Games, terminology and more...
The concept of the futuristic space elevator as an inexpensive alternative to space rockets explained by Andy Darnley