In the age of social media, when cell phones come with camera lenses optimized for selfies, that last question gets asked regularly. So I am going to answer it, once and for all: No. There is no such thing as TMI on the Internet. We are living in a post-TMI age, and everyone needs to deal with it. Preferably by using the “unfollow” button.
There is such a thing as too much information for you. There is such a thing as information the speaker will later regret. But if an audience is willingly and pleasurably consuming the information, then by definition, that is the right amount of information for them. Assuming the information in question is yours to share — your life, your ideas, your stories, your pictures, your theories about elf genealogy in Lord of the Rings — you cannot share too much of it. There are no captive audiences on the Internet. Whereas discussing your sex life at the Thanksgiving dinner table may be TMI for Grandma, discussing your sex life online does not necessitate Grandma’s participation. If you follow someone on Twitter and you find that her tweets are too much for you, then you may unfollow her. If you continually recoil at TMI, it's because you lack the willpower to stop consuming (or foresight to avoid) the information in question. That’s your fault.