My first impression of Hoi An (population 75,000) was that it was buried under tourists, hot, had persistent vendors, and all the buildings were yellow. It reminded me a great deal of Chiang Mai in Thailand (okay, the buildings there aren't yellow), a place overwhelmed by its own popularity. In a city the size of Bangkok, thousands of tourists can disappear among the natives and hardly be seen. But this kind of popularity in a small town is a mixed blessing for locals and visitors alike. The locals prosper on the tourist trade, but become subjects in the fishbowl. And a very small town like Vang Vieng (in Laos, population 25,000) loses all culture of its own, assuming a pure backpacker personality. For backpackers it means its easy to find english menus, western food (if you want it), laundry services, internet cafes, and book exchanges. But it also means that your tenuous contact with the local culture becomes even shakier, and you don't feel like you're discovering anything new. That was probably never true, but at least it felt like it when you were in a large town with few foreigners.
When you get off the tourist trail, the backpacker support structure can get sparse. In Ninh Binh (population 53,000) there are a number of hotels catering to tourists offering tours of the local sites that took me there, but not many foreigners. In Vietnam you can count on internet cafes used by the locals even in the smallest towns, but that isn't the case in other countries. Tha Khaek, Laos (population 70,000) had no internet connections at all! The first time I went to my favourite internet cafe in Ninh Binh (on a back street several blocks from the hotel cluster) all the kids (ages 8 to 15) had to say "Hello!" or shake my hand, with the occasional "Merci beaucoup!" mixed in. They spoke no english, but I was a huge hit anyway. A couple tried on my sunglasses, a few others investigated Lonely Planet's Vietnam. You don't get this kind of greeting in Hanoi or Hoi An, but you do get it off the trail. It's both heart-warming and disturbing. They're very friendly, but it's because you're so ... unusual. An ironic reversal: the backpacker becomes the one in the fishbowl.