Of course, Twitter attributes this decline to its efforts to combat spammy tweets, but there are two other explanations to consider.
1. Notice the chart shows percentage of spam, not actually numbers. Could it be that actual spam tweets are on the rise, but the percentage is down due to an even faster growth of legitimate users? I’d love to see the actual numbers.
2. When a network plateaus are the spammers the first to show signs of fatigue? Is this decline a sign that Twitter users are simply not engaging as much these days–even with spammers?