Real estate commissions are becoming a point of controversy. Home values in many areas have quadrupled over the past 20 years. This may be contributing to the increased number of licensed agents and growing competition between them. The number of real estate agents in areas tends to rise when home values do, and the productivity of existing agents goes down. The rewards have increased, but so have the demands of clients and business risks faced by agents. In North America, agents have had to become familiar with marketing through the internet as well as traditional print and other media. Additionally the law is complicated with issues such as defects in housing, grow houses and other issues of which the agent is the front line defense for his client. There is more liability than ever in advising buyers and sellers.