At the moment there are some discussions about bots at the Second Life blog. I like to read things like this:
The site for the most popular commerial bot openly graphs how many active bot logins there are. Right now its at around 2000 avs on grid. Another program that used to be popular now accounts for only 200 live on grid.
Read (and write) on here: https://blogs.secondlife.com/thread/1051