

One in every 20 computers
No, it could be 1 in 20 computers. It could be more than 1 in 20 computers. It could be less than 1 in 20 computers. 5% of the page views, of sites that Statcounter tracks, are reported as Linux machines. There is no way to know what percentage of machines are Linux from the Statcounter reporting as it is.
Yeah, that’s a good question. I don’t remember reading any documentation from Statcounter speaking about how well that bot detection and removal algorithms work. The last company I worked for did data collection, as we recorded all kinds of metrics from users. We had a team that focused on bot detection. Mostly it involved discovering the bot net and then removing all of their metrics that were accounted for in the system. Then updating the bloom filters so that any further metrics from the known bots would be ignored. Companies were paying millions of dollars for our contracts and every click was getting itemized and charged for. So, trust me, it was very important for my old company to discover and eliminate bots aggressively.
Statcounters sells their statistics and not the data from what I understand. So it does beg the question, how aggressive are they?!