This was apparently an ending theme for her radio show, "Haniwa My House," a long time ago. The radio show itself is still being broadcast every other week, but I don't remember hearing this song in it, so I assume it's been replaced at least an year and a half ago.
From what I can hear, a lot of effort went into making these songs. Unfortunately, her singing isn't quite up to snuff. It's not that bad, though. I like the third track most among the three.
By the way, I'll have to assume that this didn't sell that well. I got this in July of 2005, almost 4 years after the release, yet I was easily able to pick up a first pressing one. Then again, maybe it's the first pressing version that didn't sell well. After all, who wants to pay Y2,300 extra for a T-shirt?
Note that this was also part of the "Thank you for coming to Fanimecon 2004," "Maria-chan Appreciation Purchase."