Query: Which season had the biggest voting controversy?
Context: Voting results have been a consistent source of controversy. The mechanism of voting had also aroused considerable criticisms, most notably in season two when Ruben Studdard beat Clay Aiken in a close vote, and in season eight, when the massive increase in text votes (100 million more text votes than season 7) fueled the texting controversy. Concerns about power voting have been expressed from the very first season.