Interestingly, marketing is also important in scientific research. Having the right name for a scientific field is extremely important for the development and popularity of the field (e.g. to obtain grants or people's attention).
A consequence is that many scientists tend to follow the trend by qualifying themselves with the most fashionable name. For example, those who used to work in "Artificial Intelligence", worked later in "Data Mining" and then in "Machine Learning". One advantage is that this tends to mix people from different communities, but the drawback is that this blurs the distinction between domains and hence may be detrimental to the image of the field since it may lead to a lack of unity, lack of formalism, or lack of common language.
Another consequence is that theoreticians (e.g. people working on specific mathematical domains) are encouraged to pretend that their work has applications in the currently fashionable domain. One advantage is that many domains get formalized and "cleaned up" when mathematicians get involved, think for example about Quantum Mechanics and Von Neumann, or more recently, Spin Glasses and Talagrand. However, there is always a risk that theoreticians keep doing what they are good at (e.g. keep working on their own theories), and ignore the specifics of the application domain.