Question

A technique that could continually or continuously track what exactly a person thinks...

Note:
1) By technique, I dont mean any external means...i.e not using some fancy bio-electronic gadget that reads the electric signals of our brain...
2) I have assumed we only think of only one thing at a time. Sub question: Is it possible for a person to
think more than one thing at a time? Why or why not?

i) Do you think, that this can indeed be implemented?
Note:
It seems 'continually' may be possible. For example consider this technique:
--- We have an alarm that goes off every hour and we decide the following: whenever the alarm
goes off we 'interrupt' our brain and think about what we are thinking. --- Again, is this method
implementable? It has some caveats:
a)Suddenly if somebody asks us what we are thinking, will we be able to?
b) This technique may affect our 'normal' thinking.

ii) Assume this technique can be implemented. What are the ways in which this technique can be used?