The first hand sign of the circle made with index finger and thumb would seem to indicate that what you are reading (or absorbing) rings true to your current sense of the matter, or that it is a good or appropriate message which appeals to you, in that it is something that you would want. It may even be that this sign is an indication the message you are receiving concurs with your own, and may indeed even further support your developing understanding of the particular objective you have afoot.
The second sign of the raised index finger may be a subconscious or automatic way for you to verify and recognize the importance of the incoming message, and perhaps also a way for you to log it more importantly into your conscious memory, as the primary or principle point to consider. Conversely, it may also mean a “wait a minute” or “slow down” objection worthy of further review or hashing out. Nevertheless, it is still an indication of a prime point to regard in your further deliberation of the matter you are currently taking in.
On the other hand, it could just mean “Nice One!”