There is no single goal or partisan affiliation.
Here are a few of the many reasons people are protesting:
1. More than 16 million Brazilians live on less than $44 a month.
For perspective, $44 is less than half what the average American spends on coffee in a month
2. Brazil's minimum wage is around $320 a month
3. Many workers commute 2-3 hours each way on Brazil's public transit
4. Brazil's schools are ranked 39th out of 40 major nations
5. Some are enraged by the passage of "gay cure" legislation...
...which was pushed by Marco Feliciano, a prominent evangelical pastor...
... who is also the President of Brazil's Human Rights Commission
6. Brazil's spending on the World Cup and Olympics
Within the context of all of these problems – especially the rampant economic malaise – people are upset that their tax dollars are being used for building stadiums for tourists instead of feeding the millions of Brazilians who suffer from hunger.
The government is spending at least $29 billion to host the 2014 World Cup and 2016 Olympics.
The amount spent on soccer stadiums for the World Cup could build 8,000 new schools
7. What sparked the protest? Proposed bus fares increases.
If you're making minimum wage ($320 a month), then taking the bus to and from work will cost about $82/month
...which is 26% of your income
So, you can probably understand why people are frustrated
The protests in Brazil don't have one lone cause.
"Fueled by multiple grievances, from the poor quality of public services while millions of reals are spent to build football stadiums to revulsion against a political class seen as largely corrupt and self-serving, rallies held in more than 100 cities conveyed above all a deep sense of exasperation with the country's slow pace of change.
The sentiment is especially strong among the young emerging middle class that took to the streets. Beneficiaries of two decades of democracy with economic stability, they bought the dream of a more prosperous and equitable Brazil drummed up by their leaders and are now saying that it is time to start delivering."