All nouns are capitalized in German!
In English only proper nouns such as people's names are capitalized. In German, however, every noun is capitalized: Mann, Frau, Mädchen, Apfel, etc. The good news is that this helps you tell nouns apart from other types of words.
In German (and Luxembourgish), all nouns are capitalized. This was also practiced in Danish before the spelling reform of 1948, and in English during the 18th century (as in Gulliver's Travels, and most of the original 1787 United States Constitution). (wikipedia, capitalization)
-ung seems to be loosely equivalent to a gerund-making -ing (and such words are feminine). Some nouns are abstract--I think the grade school rule in English gets extended to person, place, thing, or idea. You can't touch die Chemie, for example, but it is nevertheless a noun.
More on German capitalization rules: http://german.about.com/library/weekly/aa020919a.htm Apparently it has been up for debate in the past.
Maybe I'm stating something obvious here that has already been discussed at length, but in the descriptions/summaries for the German lessons (for English speakers) all the nouns are shown with small letters (e.g. business - "bestellungen, laden, kleinanzeigen, beitrag, beratung, artikel, kasse"), which is plainly wrong and would not occur under any circumstances.