In most circumstances, it’s the small things that count. The smallest details which make a service so awesome. As with most of Google’s products, there are a ton of hidden gems. But the single – most useful – feature is in Gmail.
The ‘+’ tagging of email
I’ve been using it for so long, that I probably take it for granted, but I recently realised that not many people use it, or even know it exists. I’m sure that it’s also available on numerous other Email providers, but I use Gmail, so who cares about the rest…
This function is particularity useful for signing up on various sites, assigning filters or just plain labeling emails for various uses.