Last week, BoomTown posted on the amazing number of Joker impression videos related to the hit Batman movie, “The Dark Knight,” that were popping up all over the Web.

Next up?

Well, it seems the honor will be going to Harry Potter knockoffs and tributes, due to the upcoming sixth movie in the series about the boy wizard, “Harry Potter and the Half-Blood Prince.”

The movie is set to be released Nov. 21 and focuses on the early life of evil Lord Voldemort, when he was only a creepy orphan named Tom Riddle.

Here’s a video, below, of the actual trailer, which was recently released online and is playing in theaters.

And below that is a good example of one of the many user-created videos that tout the new Potter movie by using old clips to create new trailers. None of them is sanctioned by Warner Bros. (TWX), which is releasing the movie and will not likely discourage the phenomenon, as it builds excitement for the film.

Here’s a curious trend I’ve noticed developing quickly on YouTube, probably because of the acclaim that the late actor Heath Ledger’s performance as the Joker in “The Dark Knight” has garnered.

His memorably malevolent turn in the latest Batman movie is likely to result a posthumous Oscar for Ledger. But perhaps more interesting is the number of fans who are doing video impressions of his performance, acting out various scenes from the movie, and posting them online in tribute.

Here are just such few videos, including ones that are dead serious and others not so much, as well as a compilation of Ledger’s various scenes at the end:

Joker/Batman Spoof

Joker Interrogation Scene

Joker Mob Meeting Scene

Joker Party Crashing Scene

Joker “Why So Serious?” Scene (as channeled by Hayden Black of “abigail’s ‘x-rated’ teen diary”)

Heath Ledger as Joker Compilation

It is hard to look away from the swirl of media that the untimely and tragic death of Heath Ledger has engendered, and the Internet has jacked the frenzy into overdrive.

Along with an explosion of Web stories and video about the late actor–unfortunately too, please-don’t videos from outside the home of his family seem particularly appalling–there has also been controversy around a very prominent online marketing campaign that has been going on related to the next in the blockbuster Batman series, “The Dark Knight.”

Why? Because it has been focused almost exclusively on Ledger, who plays what appears to be a very warped and malevolent version of the villainous Joker (pictured here).

A terrific story in The Wall Street Journal yesterday looked at this Internet-aimed marketing effort around the Warner Bros. movie, set to come out this summer.

It’s been a slowly unfolding viral campaign online, stretching three-quarters of a year now, almost all focused on Ledger’s Joker character. It began in May with a site showing a fictional district attorney candidate, IBelieveinHarveyDent.com (still up) and then another with a defaced picture and clues, IBelieveinHarveyDentToo.com (now you only get a “page not found” message).

There have been lots of efforts like this with sites like the Gotham Times and a scarier version called the HaHaHa Times.

And, of course, the many trailers, seen below, which are all over the Web now.

But now that the already creepy online effort has taken on an even more macabre tone, one wonders what Warner Bros. will do.

Or, because this is the Web, where things tend to spin out of the control of media companies, whether the movie company can do anything at all.

Here’s some trailers, all of which are pretty amazing: