Cloud computing is the fastest growing segment in the software industry today (with a Compound Annual Growth Rate of 27% as per industry analysts). The rate of adoption is fastest among certain industry sectors such as Professional Services, Media etc. But the trends also take into account that many organizations that are >10+ years old have made significant IT investments in on premise systems. So, rather than a "rip and replace", we will most likely see a continued coexist strategy built-into Cloud computing, where newer, more agile Cloud applications will need to interface and integrate with Enterprise, home grown and legacy systems (i.e. "untouchable" due to security, corporate standards, regulatory certification or other factors).