directory of services in the cloud

directory of available API's in the cloud are available here:

http://www.programmableweb.com/apis/directory

the list shows two things

1. there are lot of services out there many of them can be used free of charge
   
   but
   
   
2. the stability of usage is a huge problem
   - few listed services are moved or removed completely
   - few service definition often changed without providing a sufficient version management