If Twitter were really serious about the dangers of sharing access to Gmail accounts, and thus their personal documents on Google Apps, they wouldn’t continue to encourage people to hand over their email passwords just to tell their friends about Twitter or find existing friends on the service.
Blogcatalog have just launched an API for programmers giving extensive access to the data contained within both the user profiles and blog profiles.
The BlogCatalog REST (REpresentational State Transfer) API allows the retrieval of public user and blog data based on a set of input parameters. This page outlines the various types of requests that can be executed and provides example requests and responses.
Rose seems to think that Blogcatalog is just a MyBlogLog clone. I have just spent about 2 hours drawing up a list of the current differences between each service, that I believe is able demonstration that both services are being developed by a team that truly want to differentiate their offerings, though sometimes there is some healthy competitive overlap.