I’m quite new to the site…
And yes, of course OGS adjusts your rank as you play more and more ranked games — wouldn’t make much sense if it weren’t so.
You can watch your rank changes in the “Statistics” part of your profile. But just one word of caution: Don’t focus too much on rank — this can severely spoil a lot of the fun in Go. My recommendation is just to play as much as you can and like to play while using automatic handicap (which is calculated by the server) so that both opponents always have 50/50 chances to win.
…and do friendly matches affect the rating?
Ranked games affect your rating. “Friendly Match” is just the title of the game. It will say “Ranked” if it is ranked and those are the games that will affect your rank.
To expand on @crodgers’ explanation:
For a game to affect your rank, it needs to be …
- a ranked game, AND
- your opponent must NOT have a provisional rank.