Their site has a page that explains the name Dasa, and I quote:
Even though the place may not look attractive on the outside, I'd still say it's one of my favorite haunts."dāsa" came from the name of the late venerable Thai Buddhist Monk called "Buddhadāsa Bhikkhu".
The word "dāsa" itself means "slave" or "servant". It's the word from an ancient language called "Pali" which is the language that Buddhist monks use in chanting and in their regular rituals or ceremonies. We chose this name because it conveys the meaning that all book lovers are "slave" in the sense that they can't live without books or reading. The name also has a nice Asian touch to it and is also quite catchy.
Inside it's cozy
and conducive to browsing.
Sometimes I would climb up the second and third floors and browse some more
Often I just stay in this area where the English-speaking assistants are. A white guy (I'm guessing the owner) works quietly near the coffee corner cataloguing books in his computer.