For a very large variety of reasons, My Immortal has been suspected of being a very elaborate trollfic (see more information at Tara Gilesbie). The most notable reason for this are a very large amount of textual and story elements that might be references to works that a mentally stunted twelve year old girl presumably wouldn't show interest in. These range from complex literature to extremely obscure movies and media factoids.
Some of these seem to suggest that Tara, or whoever is behind her persona, is either an actual literature and gothic subculture fan messing around, or someone smart enough to dig up said facts. Or both.
Some of these have been taken to be rather lucky mispellings (see: the Tom Bombadil incident), and that they are entirely accidental. If this is the case, however, then some truly spectacular coindidence is at work here.
Note: do not list outrightly admited references. This includes the Buffy the Vampire Slayer reference on Chapter 31, which is followed up by an entirely unsubtle "bufy rox!111", or the various things with "geddit" or some variation following them.
Lord of the Rings
In Chapter 31 young Voldemort is introduced as "Tom Bombodil". Tom Bombadil is a character in J.R.R. Tolkien's The Lord of the Rings. Not only is he a minor (but very memorable) character, but he's also absent from the movie adaptations. Therefore, this means that Tara must have read the books (or have done some research on them); as such, this is often used as foremost evidence that she is in fact a well-read troll.
Notably, in the next chapter she dismisses the name, calling it "a mistak". This is probably to throw off suspicions of her being a troll.
Similarly, young!Voldemort is also refered to as "Tom Anderson" or some variation thereof by Proffesor Sinister. Tom Anderson, better known as Neo, is the main protagonist of the The Matrix trilogy, which is a deeply philosophical film series. However, because many goth and emo teenagers appreciated these movies for shallow aesthetics (read: all the leather), this would be in character for Tara's ditzy, edgy persona.
Hedwig and the Angry Inch
My Immortal's description of Hedwig may be a reference to this play/movie. Instead of a snowy owl, Hedwig is a blonde "goffik bi guy!!!!!11" with an interest in music. Combined with his presence in the eighties, it seems to uncannily match the titular Hedwig of Hedwig and the Angry Inch (though the character undergoes sex surgery and is female for most of the play/movie).
Hedwig and the Angry Inch, dealing with rather uncomfortable subject matters and generally being a more niche work at the time of My Immortal's creation, would be a fairly large red flag for Tara being a troll.
James Potter's gothic name is Samaro. Although Tara claims that the name is an homage to The Ring, there is an actual town in Pakistan called Samaro, which was originally called Jamesabad (literally, "Jamestown").
Though it could easily be a mispelling of "London", Longdon is an actual name for multiple villages in the UK.
In Chapter 43 Mr. Norris says "this job would be great if not for the fucking students". This line is taken almost ad verbatim from Kevin Smith's Clerks, the only difference being that the character saying it (Randal Graves) is refering to customers and not students. As far as references go this is arguably the most explicit.