The unexpected victory of the American colonists over the British in
the Revolutionary War had a great effect, of course, on 2 continents,
Europe and N.America, but it also had a considerable effect on a 3rd
continent. In fact, the american victory served to populate this 3rd
continent.

What is the 3rd continent? Why did the colonists' victory help to
populate it?

Dear egabb,

The third continent was Australia. Before 1776, many British convicts
were sentenced to transportation to the 13 North American colonies.
After the rebellion of the colonists started and finally led to
American independence, the British criminal justice system needed to
quickly find an alternative, since prisons in England were full.
It was decided to start transporting convicts to Australia. The
continent was only known by its coastline then, and had no European
settlements at all. But the area of today's Sydney, Botany Bay, had
been proclaimed British territory by discoverer Captain James Cook
several years ago, in 1770.
So in 1788, the first fleet with convicts from British prisons and the
soldiers guarding them arrived in Botany Bay, and they established a
prison colony, which was the very first European settlement in
Australia. Others, also non-convicts, followed.
Had the American Revolution not happened, it had very likely taken
some more years or even decades before a European nation became
interested in the continent Australia. Settlement and development
would have started much later and most likely not under the British
flag, but in the name of France, since the French were looking for
possibilities to compensate the loss of their colonies in North
America and India during the Seven Years War (1756-1763).

Sources:

British Public Record Office: Transportation to Australia 1787-1868
http://catalogue.pro.gov.uk/Leaflets/ri2235.htm

British Public Records Office: Family History - Prisoners and
Transportation
http://www.pro.gov.uk/pathways/FamilyHistory/gallery5/prisoners.htm

Australian Storys: Sträflinge - die ersten weißen Australier (in
German)
http://www.storyal.de/australia2000/rocks.htm

Search terms used:
transportation america " australia" 1788 1776
://www.google.de/search?hl=de&ie=UTF-8&oe=UTF-8&newwindow=1&q=transportation+america+%22+australia%22+1788+1776&meta=
"james cook" "botany bay"
://www.google.de/search?q=%22james+cook%22+%22botany+bay%22&ie=UTF-8&oe=UTF-8&hl=de&meta=

Hope this answers your question!
Regards,
Scriptor