Losing money to donks.

So this guy comes to the table called sohosoho on pokerstars and his first hand goes a little something like this: http://www.pokerhand.org/?788109 Im thinking "what a lucky donk!" so the next hand i play with him i make sure i take advantage.

Im dealt 9J and just limp in. The flop comes 678 and i bet out, he calls. River is a 10! Now i have the nuts and check it. He bets out $50 into a pot of $9!! Im thinking.... ok... He must have a 9 and probably has a J too so i raise him all-in for $300 with the nuts.

He quickly calls with 94. Flop comes a J for a split pot and every1 calls him a donk. That river was just sick and cost me about $150 there, such bad play by him.

http://www.pokerhand.org/?788115

Bankroll: $526