@Tomberry
> the first and second videos
Yes, it might be said that he is a sub-meme of Shuzo Matsuoka.
His name is "Robert". it's uncertain what he is. But it's said that he is a TV crew of Japanese TV show "食いしん坊バンザイ" (lit. Viva big eater) hosted by Shuzo.
The video that Robert appears on is a making video of that program taken at San Fransisco and was posted to Shuzo's web site. In the video, by Shuzo's mischief, Robert was suddenly ordered to explain that situation in Japanese with 5 seconds. Naturally, he had no ready answer. So, he was confused and could do nothing but shouting weakly.
The reason why he became a MAD resource is that his all wet, weak shout and facial expression being at a complete loss were really funny and were loved among Shuzo's fanatics.
The video was posted to Nico Nico Douga on Oct, 2008 and became additional MAD resource of Shuzo's fad around May, 2009.
On NND, MAD videos related to him are tagged as "ロバートの将来性(Robert no Shouraisei, lit. Robert's potential)". Now, there are about 130 videos on NND.
Nico Nico pedia
http://dic.nicovideo.jp/a/%E3%83%AD%E3%83%90%E3%83%BC%E3%83%88%E3%81%AE%E5%B0%86%E6%9D%A5%E6%80%A7
Search result on NND
http://www.nicovideo.jp/tag/%E3%83%AD%E3%83%90%E3%83%BC%E3%83%88%E3%81%AE%E5%B0%86%E6%9D%A5%E6%80%A7
> the third video
This is a CM of a poultice "のびのびサロンシップ (Nobi Nobi Saron Shippu)" and the man is famous Japanese actor Naoto Takenaka.
As you can tell from several MAD videos, his funny face expression and acting are suitable for MAD resource. Because of this, some MAD editors choose this to their MAD resource.
This CM started to be reused in MADs around Feb, 2009. However, the amount of videos of the moment are 66. They are not so many. Moreover, this original CM itself never became popular in Japan. And also, its funniness has never been picked up by any Japanese media.
It always happens that MAD editors choose their MAD resource just because it can be fit for their (poor) way of MADs style. This case is one of them.
Therefore, I think it's not so notable.
Nico Nico Pedia
http://dic.nicovideo.jp/a/%E3%81%AE%E3%81%B3%E3%81%AE%E3%81%B3%E3%82%B5%E3%83%AD%E3%83%B3%E3%82%B7%E3%83%83%E3%83%97
Search Result on NND
http://www.nicovideo.jp/tag/%E3%81%AE%E3%81%B3%E3%81%AE%E3%81%B3%E3%82%B5%E3%83%AD%E3%83%B3%E3%82%B7%E3%83%83%E3%83%97