Ah yes, the pratfalls of modern day existence. True my wife does enjoy seeking out new waymarks with me, but it wasn't easy back when it was just Quonset Huts and Water Towers. (Although our son still yells from the back seat whenever he sees a water tower and is probably the only 5 year old who knows what a quonset hut is.)
The categories created throughout 2007 seemed to have more of the proverbial Wow factor (read fun factor). Coughing up the cash for premium membership to be a part of many of those categories also helped. Hopefully, we'll keep it going.
If I were still single, I'm sure I'd be dragging somebody along, at least as much as I could. I enjoy sharing the find as it happens just as much as when I post it.