Life In 19x19

Just a short question (I admit I am too lazy to look it up in the ranking system description):

Does it make a difference if I win (or loose) against a strong or a weak opponent of a certain rank?

That would mean that a win against of a strong 5 kyu (almost 4 kyu) counts more than a win against a weak 5 kyu (who just made it across the barrier from 6 kyu).

I think so. As I understand it the system works on the internal non integral rank.

It also matters if your opponent's rank changes after you play him.

Li Kao has it right. The system internally uses a floating point rating that you can see in the rank charts for users. Then this floating point rating is converted to a rank like "1d" that is shown to you. But internally, it stays floating point, so a strong 1d is counted as stronger than a weak 1d.