Ever since Blogger Engineering completed the emergency upgrade to support Windows Live Writer , we've seen demands from people who use similar offline editors, and other third party products. The "ClientLogin" protocol (aka OpenID 2.0) was replaced by OAuth 2.0 (aka OpenID Connect) , last month. As the problem with Live Writer was diagnosed, in a joint effort by Blogger and Microsoft, we saw evidence that Live Writer was not the only offline editor , that needed attention. The problem is not with Microsoft is with ALL external soft. Do not work with Zoundry Raven, BlogJet, Post2Blog, PowerBlog Personal Client, W.Bloggar, Windows Live Writer, etc. Blogger is about personal choice, however - and some Blogger blog owners use offline editors that are not produced by Microsoft.
What Blogger won't tell you