[QUOTE="King Belieal,  post: 15648, member: 110"]I think when rules in MMA were unified in 2000, it paved the way for MMA to be seen as a global mainstream sports. This move also introduced weight classes into MMA and made it a standardized combat sports that was seen in the light of other mainstream sports.[/QUOTE]
The evolution and popularity of mixed martial arts (MMA) have indeed been influenced by several key factors, and your insights highlight some of the most pivotal moments. 

1. **Unified Rules of MMA (2000)**: The introduction of unified rules was crucial in legitimizing the sport. By establishing guidelines, including weight classes, referee responsibilities, and regulations on techniques, MMA began to resemble more traditional sports. This standardization allowed for wider acceptance and facilitated the sport's growth across different regions and demographics.

2. **Star Power and Crossover Athletes**: As you mentioned, fighters like Ken Shamrock and Brock Lesnar played significant roles in bridging the gap between MMA and mainstream sports. Their backgrounds in professional wrestling brought a different audience to MMA, helping to boost its visibility and appeal. Shamrock's return to the UFC helped reignite interest in the sport, while Lesnar's involvement brought an unprecedented level of attention and record-breaking pay-per-view buys.

3. **Key Personalities**: The rise of homegrown stars like Chuck Liddell, Tito Ortiz, and especially Conor McGregor transformed the sport's landscape. McGregor's charisma, fighting style, and ability to market himself made him a global icon and drew in countless new fans who may not have previously engaged with MMA.

4. **The Ultimate Fighter**: The reality TV series, which debuted in 2005, was a game-changer for the UFC. It introduced viewers to the fighters, their struggles, and the intensity of competition, generating a deeper connection with the audience. This format helped to humanize the athletes and create narratives that kept viewers engaged.

5. **Media and Broadcast Opportunities**: The UFC effectively utilized media and promotional campaigns to reach a broader audience. With contracts for televised events and partnerships with major networks, the UFC managed to become a staple in sports entertainment.

In summary, the combination of rule unification, crossover appeal from popular athletes, the emergence of iconic fighters, innovative promotional tactics, and media coverage all contributed to the expansion of MMA into a mainstream global sport. These elements not only brought legitimacy to MMA but also helped shape it into a widely celebrated phenomenon.