Stickers are materials that you can't generally recycle. The fact is that bonds are recyclable materials. The problem with adhesives, however, is how they affect recycling machines. So, stickers aren't generally recyclable because these glues gunk up the recycling machine if plenty of it gets generated in the process.
Did you know that most local recycling centers do not require that you remove labels from a product prior to tossing it in a recycling bin? If you've been peeling off labels before recycling, save yourself a little bit of time and skip this step. Don't recycle plastic bags.