Football (Soccer) is by far #1 sport in the world. No doubt about it. It is played everywhere.: America (north and south), Europe, Africa, Asia, even Oceania.
Motorsports,Rugby,Baseball,Golf and American Football are sports with limited appeal (as its attracts only a certain section of viewers) and its only popular in one particular country.
That is not 100% true.
Rugby: it is followed in all Commonwealth countries (except in Asia). Then, it is rather popular in France, Italy and Argentina. Not much outside these countries.
American Football: just US.
Baseball: you can find good baseball in all the american continent. USA (of course), but also Canada and Latin America. Baseball is loved in Mexico, Puerto Rico, Cuba (it is a religion over there), Dominican Republic. Also in Colombia and Venezuela you can find good teams. And don't forget the Far East countries, like Japan and South Korea, where baseball is extremely popular. Also in China baseball is having some popularity. What about Europe? Netherlands, Italy, but no more than that.
10 Countries play Cricket
That's the "problem" of cricket. If you count the raw numbers, you have billions of fans. But where are they located? In one specific area: the subcontinent. But if we go outside the subcontinent, where can we find good cricket? Very hard...
In the american continent (with the exception of the Windies) cricket is almost unknown. An example:
http://www.tsn.ca/
This is the most important Canadian internet site about sport. Canada was involved in the cricket world cup. If you want to find info about cricket on this site, you have to go through the OTHER SPORTS page and maybe you will find a short article. In Europe (with the exception of the British Isle), cricket is unknown.
Africa? Ok, there is some very good cricket (South Africa) and decent cricket (Kenya, Namibia)... But apart from those countries?
Asia? If we exclude the subcontinent, where can we find good cricket? Almost nowhere.
Oceania? Excellent with Australia and New Zealand.
If I had to choose the 2nd most popular sport in the world after soccer (which is by far #1), I would pick basketball. It is played at very high level in all the american continent (Canada, USA, Brazil, Argentina), in all Europe (except the British Isles: Spain, France, Italy, Germany, Greece, the former Yugoslavian countries and RUSSIA).
Asia? Well, there is China. Basketball always had a good tradition in China and with Yao Ming playing in the NBA, basketball has reached high levels of popularity.
Oceania? Definitely basketball is not as popular as cricket or rugby, but Australia and New Zealand are good basketball teams.
Just a comparison. How many countries are members of ICC? 97. How many countries are members of FIBA (Federation international de Basketball - International Basketball Association)? 213.
So: if we count the raw numbers, Cricket is undoubtedly a very popular sport around the world. But, actually, it is played at a good level only in very few countries. Just think of this: only 10 nations are allowed to play the highest form of the game (test cricket). I find very hard to consider cricket the 2nd most popular game in the world, when outside those 10 nations, the game is almost unknown.