Every time I use GMail, I seem to make a mental note of the count of messages in my spam folder. And a while ago I thought it might be interesting to plot the count of spam messages over time, and see what happens.
The GMail spam filtering is excellent, and it is extremely rare that an actual spam gets through to my inbox. The default behaviour is to keep spam for 30 days, then delete them. So this system can be seen as an averaging filter, a sliding window giving a 30-day average of daily incoming spam.
Early this year, there was a huge spike in spam, and I remember having a level of over 1,000 spam for quite a while. In recent times, things have settled somewhat, and as the chart below shows, spam actually seems to have dropped off. From an average of over 20 a month or so ago, it has now dropped down to around 15:
Since I have been very careful about exposing my email address to spam harvesting, I may get less spam overall than people who actively post to newsgroups and so on, but the interesting result from this is more the overall downward trend than the absolute numbers.
The above data was collected and plotted using Google Spreadsheets, and uploaded with Skitch.
