I heard this song on today's edition of NHK's "Nodo Jiman"（のど自慢）and I finally decided to profile it. Not being a fan of pop band Ikimonogakari（いきものがかり）per se, I still enjoy the inspiring feeling of "Arigato" (Thank You) as this cheer-up song. I've heard the band's 18th single a number of times over the past few years including a recent Kohaku Utagassen.
The theme song for the NHK morning serial "GeGeGe no Nyobo"（ゲゲゲの女房...GeGeGe's Wife）which was televised for most of 2010, the show starred actress Nao Matsushita（松下奈緒）as the wife of manga artist Shigeru Mizuki（水木しげる）as the story related how they had to endure the tough times before Mizuki finally found success with works such as "GeGeGe no Kitaro"（ゲゲゲの鬼太郎...Kitaro of the Graveyard）. As is the case with all of the asadora, there were episodes which ended with a cliffhanger or some sort of tragedy, but I've got a feeling that Ikimonogakari's theme song reassured viewers that things would inevitably turn out all right.
In that 2010 appearance by Ikimonogakari, their performance was prefaced by Matsushita's own version of "Arigato" as an accomplished pianist. A recorded version is available on a BEST compilation from that same year, "Scene 25 ~ Best of Nao Matsushita".