The 3DS's StreetPass function is nice to have, but the 16 character limit restricts any real information being shared, with no option to enter a Friend Code either. There have been numerous website workarounds, with the latest being PassID.
Visitors can sign up for a profile displaying their Mii, Mii QR code, Friend Code and a short biography. The site then generates a web address short enough to fit in your StreetPass quote: passid.ca/jn for example.
If someone uses your link to add you as a friend on the site you'll receive a notification, prompting you to add them to your own friends list and your 3DS list if you so choose, a godsend as the console itself has no friend request notifications, of course.