Richer (annex 1) countries can help developing countries to achieve sustainable development and limit GHG increases and then claim some emission reductions for their own targets
The clean development mechanism allows governments or private entities in rich countries to set up emission reduction projects in developing countries. They get credit for these reductions as 'certified emission reductions (CER's). This system is different form the Joint Implementation as it promotes sustainable development on developing countries.
For all these CDM projects and the Joint Implementation schemes, mentioned before, its important to establish a baseline so the real change in GHG emissions can be assessed and to make sure no-one cheats. Still, CDM could mean lots of money and increased investment in developing countries.