Card counting is much less effective in online Blackjack compared to physical casinos due to several factors. Online casinos often use random number generators or reshuffle the deck after every hand, making it impossible to track cards. Additionally, many online games use multiple decks, which further complicates card counting. In live dealer games, automatic shuffling machines or quick reshuffling between hands also reduce any potential advantage. Furthermore, online casinos monitor player activity more closely, and counting cards can lead to account suspensions. Overall, the combination of these factors makes card counting ineffective in most online Blackjack games.