Err really? I'd like to make some sort of bet on this - how many phone numbers you can receive texts from verses how many email addresses I can receive texts from by some deadline. Interested? You wouldn't have to actually receive on them all of course, we'll both use sampling to check.
You are, of course, correct. There'd be a bit of a delay - I was thinking of different email providers, not creating lots on one domain. And SIMs are sorta slow to turn over. But accumulating a pile of phone numbers for trolling would not be hard.
The recent implementation of a -5 karma penalty for replying to comments that are at -3 or below has clearly met with some disagreement and controversy. See http://lesswrong.com/r/discussion/lw/eb9/meta_karma_for_last_30_days/7aon . However, at the same time, it seems that Eliezer's observation that trolling and related problems have over time gotten worse here may be correct. It may be that this an inevitable consequence of growth, but it may be that it can be handled or reduced with some solution or set of solutions. I'm starting this discussion thread for people to propose possible solutions. To minimize anchoring bias and related problems, I'm not going to include my ideas in this header but in a comment below. People should think about the problem before reading proposed solutions (again to minimize anchoring issues).