Although it is true that portuguese is very close to spanish you should note that there is a hostile reaction between members of the two groups in reading something in the other language. Especially so in South America (which by the way should not be called latin!).
There is no doubt that spanish is the third spoken language in the world, however german or french speaking users could be more. Do not forget that the penetration of the internet in the hispanic countries is still at infancy.
For your curiocity I speak greek, portuguese, german and spanish.
cheers.