1-Part of the reason these Tedtalks are so popular is because they combine both information and entertainment. Another reason I think they are so popular is because they are talking about topics that are not so mainstream.
2-Some of the speakers were using footage from the ocean. Others were using pictures
3-They all keep their audiences engaged.
4-I do think all these people are good speakers. Very effective at conveying information while keeping the audience engaged.
5-Most memorable piece was probably in the form of some media
tekwriting 