Recent Ethereum gas fee fluctuations have notably influenced DeFi user activity. On-chain data indicates that during high-fee periods, daily active addresses on platforms like Compound and Curve dropped by 15-25%, reflecting cost-sensitive users scaling back. Conversely, lower fee windows correlate with a 10-20% rise in transactions, particularly on Uniswap. Layer-2 platforms like Optimism saw a 30% uptick in usage as users seek cheaper alternatives. However, persistent high fees may drive long-term user migration to competing blockchains like Solana, risking DeFi ecosystem fragmentation if Ethereum's scaling solutions don't stabilize costs effectively.