Can you improve in chess subconsciously, over time? Years ago, I was a bullet-chess (1 min. games) addict. I played daily and often. Then I stopped for about 4 years (and played off-and-on). My rating was mediocre - around 1400 on Yahoo Chess.

Recently I started again, 3/0 games and blitz games. I noticed that I play better overall, but I can't pinpoint what it is - I just know I can see combinations better. I wonder about this a lot, because as I age I should be slightly slower mentally (I'm close to 30).
First, saying you "feel" like you're better is does not appear to be very scientific, so keep that in mind when attempting to understand the events you're describing.

Also, I don't believe what you're experiencing is related to the subconscious development of your understanding of chess, but you experiencing the difference between cramming knowledge into your brain, and what's called the "Spacing Effect".

(Let me know if this answer addresses your questions, or if there's something I'm missing.)