In general this is true! 
A bit more specific: some people only want photo cards for their UNESCO collections and some people prefer when there is somewhere written something like âWorld Heritageâ on them. Most collectors I met did not mind though.
AUS Pos does sell some nice prepaid cards with UNESCO sites, too.
Just curious - a lot of UNESCO World Heritage sites are actually a collection of sites. For example, I live in Kyoto and Kyoto is known for the âHistoric Monuments of Ancient Kyotoâ (which includes the cities Kyoto, Uji, and Otsu) for a total of 17 individual sites. If people received one card from one of these sites, do they count that as having received a card from this entire World Heritage âsiteâ, or do people want cards of each of the individual 17 sites for it to count as a complete collection? I know there are multiple examples of this type of grouping (churches, industrial sites, etc.) so was curious as to how collectors âcollectâ their sites/postcards.
I think it depends on the collector - some will count the site as âcollectedâ when they have received anything belonging to it, others will want every place that forms a part of the larger site.
I think it also depends on how big the larger site is. In Poland we have for example âChurches of Peace in Jawor and Swidnicaâ, and most people so far wanted a card from both places. But we also have âWooden Churches and Tserkvas of Southern Malopolskaâ and this site includes many places, so people have usually been happy to receive one/a few from it.
Like I said, itâs really based on how every person approaches this.
You can check how the collectors collect their unesco cards in here
https://community.postcrossing.com/t/list-of-unesco-world-heritage-postcard-collectors/21884
I see commenters mention cards about UNESCO world heritage sites.
I do not know about that, but when I visited the UNESCO headquarters in Paris in 2015, I found in the bookshop special postcards featuring mostly animals, that I didnât see being sold anywhere else.
I bought and sent some of them to friends, later during that trip, and kept some in my collection.
However, I regret not having sent them using UNESCOâs own postal service and stamps, because the shop was closing for siesta (these UN employees are too spoilt, I tell you). I was also told that the stamps for that special postal service are more expensive than regular post. In all cases, that was before I actually got to started participating in PostCrossing.
These UNESCO threads are dangerous - I thought I had enough postcard addictions to keep me busy for a while, but who am I kidding? Part of the problem is I live in a city (and country) with multiple World Heritage sites, and Iâm on a bit of a kick to collect cards from each location, not only for myself but to swap with others. That said, I have a few questions/comments that I just want clarified based on what Iâve read here on this site so far:
a photo card from the site, but it may not be a âviewâ card in that you donât really see the structure or the location, but rather a very specific part of the site. For example, a statue at a temple, a bird on the lake, etc. Iâve noticed this at a number of temples here in Kyoto and to be honest donât buy them because they are not the kind of WHS card I would like to receive.
an illustrated âviewâ postcard. In my travels in Japan I find that these are quite common, and they are often more interesting and beautiful than a normal photo view card. In some cases, they are the ONLY postcards to be found for the site.
is there really a difference between mass-produced postcards and those printed by individual photographers (or from a site like Zazzle)? Like the point above, sometimes these are the only options. I donât like âthinâ cards either, but some cards are very good, printed on proper postcard stock, and often feature better photos than the âofficialâ cards do. And, as Iâm sure many of you know, there are just some places that have no cards available and the only option is to self-print cards, especially if one has visited a particularly rare site.
Assuming that the cards are mailed from the country of origin, are the cards more meaningful/preferred if the person sending the card actually visited the site themselves, as opposed to picking up a bunch of cards from a shop or at the airport? Or does it not really matter for most people?
From what I gather, multi-view cards and series cards are the least preferred WHS cards to receive. But are there instances when people actually prefer them?
Does size matter? 
In my own collection Iâve noticed a variety of sizes of cards from WHS - many are larger (5x7), or panoramic. I chose them because the image was more important than the size/shape of the card, I wonder if this is an issue for collectors.
Does colour/age matter? That is, are vintage cards okay? What about black and white (or sepia) ones (new or vintage)? What about night view cards?
Finally, as I begin to start sorting through my cards, making a list and creating an album to share with people, I wonder if there are any tips that people may have to do this in an efficient way?
Iâm just north of the added Hopewell Earthworks in Ohio (and will be discussing them in class tomorrow). Im looking forward to getting new postcards for my Indigenous collection and extras for UNESCO collectors!
UNESCO: United Nations Educational, Scientific and Cultural Organization .