Recently at Kitchen Kaboodle, my preferred purveyor of yuppie accoutrements, I was given a shopping bag printed with an enormous proclamation reading, "Reuse me! I'm recyclable! Throw me away! I'm biodegradable!" Now, it's my understanding that bioplastics cannot be recycled. What gives?—Befuddled bagger
Try not to overthink this one, BB. The bag is "recyclable" in the sense that you can "reuse" it, meaning you can put other shit in the bag and carry it around. It's not exactly rocket surgery, though I can understand how it might be hard to think with a screaming, coked-up shopping bag in the house. ("Do me! I'm sexy!")
Still, your question raises the larger issue of bioplastics in general. On the plus side, bioplastics make people like you and me feel like we're doing something to save the planet. On the minus side, they don't actually help all that much.
Your confusion on the subject underscores the problem: since (non-recyclable) bioplastics look just like regular plastic, they often contaminate the existing recycling stream. That can render the final recycled product "weaker, or even unusable," according to ecogeek.org.
But what about bioplastics' vaunted compostability? Well, they're commercially compostable, but that's not something you can do in your backyard. Many parts of the country don't have commercial composting at all, and even here, most residential customers don't have it. Our bioplastics still go to the landfill, where—get this—they discharge the potent greenhouse gas methane as they decay.
They also make lousy plastic only suitable for disposable items, reinforcing the throwaway mentality that got us into this. In short, I'm not sold. Better would be for attractive and/or rich people to start bringing those reusable cloth bags. The rest of us schlubs will almost certainly follow suit.