In an email conversation via Cloudmark's public relations department, Landesman provided some additional insight into the numbers behind the Wired article.
For starters, the information that Cloudmark provided Wired was specifically limited to the United States for the months of June, July, and August of 2014. This is important, because the U.S. is one of Apple's largest markets; if the numbers were reported on a global scale, it's entirely possible that the percentage of spam attributable to iMessage could change significantly — and, perhaps, be less sensational.
More importantly, the data was, according to Landesman, based not on all spam, but on unwanted messages reported to the GSMA's Spam Reporting Services (SRS for short), a tool that allows users to forward spam to a special short-code phone number. This biases the data in a way that makes it hard to use in determining the seriousness of iMessage's spam problem — after all, there is no way to tell whether iPhone users are more or less likely to report problematic messages than users of other platforms. Considering the fact that study after study have confirmed that those who call Apple's ecosystem home tend to be more engaged with their devices, this is a very real possibility.
Soft numbers are hard to understand
The biggest problem with the numbers in Wired's article, however, is that percentages are relative. Without knowing the figure they're based on, it's impossible to say exactly what scale they represent.
Luckily, Landesman was kind enough to share an order-of-magnitude idea of the volume of spam messages that Cloudmark monitors, explaining that he estimates "that we've seen several million iMessage SMS spam messages a month in the United States."
By comparison, during the company's last annual shareholders meeting, CEO Tim Cook stated that the Apple handles several billion iMessage communications every day — presumably more than the 2 billion per day he reported in 2013. A rough, back-of-the-envelope calculation, then, puts iMessage's monthly traffic at around 100 billion messages.
That means that the worst possible interpretation of Landesman's estimate pins the amount of spam at 1 percent of the overall traffic. That's assuming that "several million messages" translates into "just shy of one billion," however; a more common-sense approach of, say, 10 million spam messages a month would translate into a 0.01 percent spam ratio.
All things considered, then, it's at best premature to claim that iMessage is "being overrun by spammers." While the problem is definitely real, the numbers that would support this kind of statement are simply not there.
In the meantime, if you're concerned about unwanted messages, you can simply limit iMessage to only work with people on your contact list, and report spam directly to Apple.
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