The Explorer is trotting out "slowly" for iOS users only at launch. You'll have to be patient if you're using Android, unfortunately.

The Explorer was arguably overdue. There are over 100,000 custom Lenses, according to Snap, but it's unclear how many of those see widespread use. What good is a Lens if only a handful of friends can find it? This could encourage more people to create their own Lenses knowing that they'll see more adoption. It's also an incentive to stick to Snapchat rather than switch to Instagram. If you can create and browse a giant library of AR offerings, you may not feel as much of an urge to head elsewhere.