I think people do it for a number of reasons: 1) to avoid triggering ads, 2) if they're going to relate a negative experience and don't want to put the store's name in their post and end up accused of libel or something, or 3) to avoid a digression in the thread where posters end up discussing the store instead of the etiquette issue. My preference is to either use the store's name or keep it generic ("I was at the grocery store" "I was at a big box electronics store") unless the specific store is central to the story, but I understand why people try to be specific -- nearly everyone (in North America) knows what kind of store Target is and what you can generally find there, so it's easier than trying to explain what kind of store you were at, and it sometimes makes your story more interesting if you can include specific details instead of generic.
I don't think there's any stated board policy one way or the other, though.
I understand what Hardia is saying here and I also understand most of the other posters in this thread, but I do have a couple of things:
1. The original question in this post was specifically about retailers, so while it is interesting to hear about why some people self-censor certain words, it's not really the same question as self-censor on retailers' names. So, I think "we're trying to avoid inappropriate ads" is kind of a silly reason to disguise a retailer's name. I mean an ad is an ad, they're all selling something. Is it really more appropriate to show an ad for an online school than for Home Depot?
2. I think the libel thing has been addressed by others, but in my own opinion, it's sort of a non-issue for two reasons: (a) Wal-Mart or Target or McDonald's or whoever has about a 0.000000001% chance of ever even finding this thread unless someone points it out to them and (b) all of the American judge shows that I watch assure me that telling the truth is an absolute defense against slander/libel.
3. I think that using cutesy names derails the thread more than not using them. Because if you are using the cutesy name, half of the people are going to be trying to figure out what store you meant and a lot of us non-Americans never figure it out and end up distracted from the thread trying to figure it out. And if you're using "BullsEye Store" because you're worried that if you write "Target" it will derail, well, why wouldn't you just write "Department Store" or whatever.
The bottom line for me is this: If the author of the post wants the readers to know which store they are talking about, they should name the store. If they don't want readers to know which store, they should use the generic "Hardware Store" or "Grocery Store". Because some of your readers will know that "BullsEye" means "Target" and some of your readers won't know. So, you're not meeting your goal of either identifying or hiding the identity of the store.
Hardia, I also want to say very clearly that I am not picking on your post. I just went back and found your post from the beginning of the thread because I think you did an excellent job of clearly outlining the major reasons why most people in this thread are self-censoring themselves and I liked how you did it and it made it easier for me to formulate my response to the thread.