Currently it seems like only the first few games matters, kind of ruins the integrity when players get placed where they don't belong, and ruin tens to hundreds of games before they actually drop to their real rank(because it is so hard to drop devisions).
Mysticman891 votesPlacement matches are just the 10 matches at the start of the season where your mmr gains/losses are much more significant compared to regular games, and your mmr at the end of them determines where you're placed. This is in contrast with it looking at your W/L record which is often what people treat it like. So (losing/winning) those first matches might put you with relatively (unskilled/skilled) players than you're used to and cause snowballing, and especially in the losing side of thing people might find themselves tilted by their first few games which sends things downhill for the remainder.
It's not clear that the underlying MMR system is less sensitive on your 10th match compared to your first though, it's more just who you're finding yourself matched with and the mentality that goes with it.
