I have never been able to keep a journal for more than a few days before I stop writing.  However, with the Moleskine notebook, I'm enjoying writing in it so much that I'm writing entries several times a day for the following reasons:  (1) The size:  This is a small notebook, only 3-1/2 x 5-1/2 inches.  I do not feel overwhelmed by writing enough to fill the page like I did in a standard size journal.  It is just the right size to fit into a purse.  (2) The quality of the paper is outstanding.  I use a Monte Blanc pen and it glides over the pages and does not bleed through to the other side.  (3) The hard cover makes an excellent board to support my writing.