I think the above comment was kind of blowing the comic out of proportion—I mean it’s a 4 panel comic it’s obviously not going to be able to give great nuance but I think it’s easy to read it as “proper” queerbaiting.

Anyway, the Wikipedia page has a good list of examples if you’re interested in mainstream examples.

Ones that stick out off the top of my head I’ve personally watched were Sherlock, and Teen Wolf and Rizzoli & Isles to a lesser extent.

https://en.wikipedia.org/wiki/Queerbaiting

One rather infamous case of Queerbaiting was with the BBC's Sherlock. Watson and Sherlock have been a popular couple for decades and the show played around quite a bit with the idea. There's lots of essays on YouTube and the net about it if you want to dig into the details, but there are many jokes in the show about Watson and Sherlock being a couple, and hints that Sherlock at least is gay/bi. The running gag is Watson repeatedly telling people he isn't gay, but he still seems jealous of other characters who have eyes for Sherlock.

All of this seemed to pretty deliberately play into the popularity of the pairing, with even a few nods to it in the show. But in the end, nothing came of it, and fans felt that they had been "baited" into watching and driving the popularity of the show without any payoff. In hindsight, the whole relationship had only been used as a joke and a lure, which was especially galling since representation of homosexuality in mainstream entertainment was still fairly rare. Thus did it receive the label of "Queerbaiting".

Now for an example of something that's not queerbaiting (though it was sometimes referred to as such) we have Steven Universe. The short version is that there was a popular pairing between two female characters in the show, and one could easily assume they were an item since they lived together and were generally only seen with each other after a certain point in the show. However, their relationship was never officially confirmed and there were hints from an artist/writer of the show that they hadn't been allowed to be as explicit as they would've liked about it.

So what makes this not queerbaiting? The biggest defense against the label is the context that Steven Universe as a whole was a very LGBTQ+-friendly show, featuring the most explicitly gay couple in the channel's history with two of the main characters. It also had a litany of other gay relationships and LGBT+ individuals. Further, the contentious couple was never officially disproven in the "it was all a joke!" sense of the previous example, it was just left open to interpretation. In total, it's clear the show wasn't using the couple purely as marketing and that the creator did genuinely care about LGBTQ+ representation.

In summation, queerbaiting isn't just "the gay couple I wanted didn't happen." There has to be a deliberate effort on behalf of the showrunners to keep people watching by heavily hinting at a payoff that will never come.

It's hard to think of off the top of my head because I admittedly have not gotten into a lot of the more popular examples, and a lot of them mix together, but a typical indication that someone is using the term wrong is if they try to point to evidence inside the show of how the couple should be canon because they have so much chemistry but the creators just won't commit and make it canon. Those are typically just people wearing shipping goggles using the word as a way to say "I want them to be canon, therefore they SHOULD be canon, but they're not, so it's queerbaiting" even though the creators have never at any point indicated that the two characters will ever be in a relationship in advertising, interviews, previous drafts of the script, or otherwise, and at most the actors may have joked about how the ship is popular or mentioned that they personally enjoy it (which isn't the same as using it in marketing or promotional material or teasing the possibility of it becoming canon). Queerbaiting can also take place even if a couple or sexuality DOES become canon if it's halfassed or skimmed over or done poorly. Some famous examples of this are Shiro and his relationships from VLD and Destiel from Supernatural.

Hibike Euphonium anime is often accused of queer baiting even though they are just friends even on the original work.

Even though Japan still doesn't have gay marriage, lgbt couples are well represented on their yaoi and yuri bubbles, so there's no need for authors to be sneaky about it and use queer bait.

There's this "kids" show called Sakura card captor from the makers of X tv...