Had a bit of a brainwave on this one.
Anyone here familiar with
QR Codes?
This only really works if your site is geo-specific/relevant, but you can just start slapping QR Code stickers onto things all over town. Walls, in restrooms, inside trains.
Very guerrilla marketing.
There are only two down sides.
First is that it's technically vandalism if you don't have permission first.
Second is that a lot of people don't know what they are, so you may have to put a little bit on it that says "QR Code" or even a link to QR Reading software for their phone, like i-nigma.
But yeah, I'm going to start doing it around town for events.