Self inquiry seems to be a popular idea, which was apparently started by Ramana Maharshi in the form of asking the question "Who am I?" The whole notion of this idea is that by asking this question, it will faciliate liberation, enlightenment, or whatever. At least, that was the notion that I had when it was suggested to ask and look into this question. The main "trap" that happened was, of course, a perversion in thought. The idea was that if I did enough self inquiry, that I would become free, or enlightened. This gave rise to a sort of superficial inquiry, where there was an assumed "I" doing an assumed inquiry, on a very mental level.
The real meat of this is of course to examine the pre-concieved notions of the "I" concept, not to give that assumed person some task to do, along a path. Who is there right now to even begin the inquiry? If we see that we are already this oneness or consciousness, then what is there to be seperate and in need of the inquiry? See that even the inquiry takes place in what you are. Look deeper into this, and expose the root of the whole production. If we see that we are already the stillness in which it all happens, then the inquiry is seen as just another passing phenomenon. Who would start the inquiry, and who would be there when it's over? All just appearance- see things for what they are, and know that you are the see-ing.