Diarrheaist refers to a person who shares too much online, particularly personal information.

“过度分享狂”是指在社交网站上分享过多信息——特别是个人信息——的人。

Example:

The blog is like a personal journal to me. It's actually more like a diary to me so maybe I am actually a diarrheaist.

这个博客就像是我的个人日志。对我来说，实际上它更像日记，所以，也许我就是个“过度分享狂”。