If you used to mine Monero for the past 2 months, you surely noticed a rapid increase in nethash. Discussing this with other community members the most of us agree that this brutal increase of net hash is related to botnets. Botnet-masters have found the way to monetize their huge CPU power, surely much profitable way then using it for useless or even paid DDoS attacks. Now, the Monero community is getting concerned because it seems that more then a half of the network hashrate is coming from the botnet-like structures. There are no adequate measures to isolate botnets from the network, although some pools, tend to fight the pest.