In channels with a lot of traffic there is normally a few memes being copypasted by several users at any given time. You would expect alterations to start with one user and other users catching on to copypaste that instead. However, often times a change is nearly instantly adopted by several users at once, indicative of a single user running a spam bot. I can imagine that multi-channel bots could monitor this behavior across channels.
Some research took me to a sketchy site providing a spam bot that appended random ints to any given message to circumvent r9k.
What are some other behavior or posting patterns that you guys have identified regarding spam bots? Anyone got any spam bot source code to analyze?