Labels act like tags in Gmail. Use them to keep your messages organized.
I've been looking through old posts and revising them to work today, in the era of the new Polymath Lab. I wanted to let you know I don't use labels at all any more (I haven't for some time). In the time since I've written this article, search functions within Google products have become so powerful they tend to be their own type of organization. In the last year or so, there's not a single email message I couldn't locate just by using the search bar.
Okay, on to the article ...
Gmail works with labels instead of folders for organizing your email messages. If it's easier for you, you can think of labels as folders, where a message can live in more than one folder. If you think back to the post about categories and tags, labels would be like tags.
Learning what labels are is easy. The more important question is how should I use labels? And perhaps even more important is, should I use labels?
When it comes to storing, or organizing some item, I tend to say, organize it based on how you will find it. Let's think about that in terms of Gmail labels. The question I always ask myself when organizing labels or similar data is, how are you going to look for these items in the future?
Let's step back for a second. Remember the post on archiving Gmail messages? Good. So, assuming you are following those general guidelines on archiving, you'd be archiving anything with a chance of being referenced again.
Okay, so you have a bunch of archived email messages. You need to go retrieve one. How are you going to do it? Will typing a few keywords into the search bar do the trick? Or do you have dozens of messages so similar to one another that you need some other means of separating them? Use how you will retrieve messages to help you shape you labels today.
So, ultimately, the use of labels will change from person to person, and rightly so. My point here is that if the Gmail search is good enough to find old messages (if you haven't tried it, do it now - it's incredibly fast and powerful), then why mess with labels at all? Just archive, and then do a text search if you need to reference something again. Also, consider looking into Gmail filters to help automate your labeling, should you decide it makes sense to use them.