This is the second episode relating to Timmy's birthday, the first being Boys in the Band.
The age that Timmy is turning is never actually mentioned in this episode, however, in previous episodes, Timmy mentioned he was 10, and today is his legitimate birthday, it's very safe to assume that Timmy officially turns 11 in this episode.
However, in Timmy's Secret Wish!, it was revealed he stopped everyone from aging, so he might still be 10, but no one else knows.
Adam West is shown acknowledging the existence of fairies. This could mean either crazy people are allowed to know about fairies since no one would believe them, or he was hypnotised and his mind was wiped after filming was done.
This is also the final episode to have Adam West's voice in the series.
This is the first (and final) time Chris Kirkpatrick does the role of Chip Skylark since "Chip Off The Old Chip". He, as Chip Skylark, briefly sang the song "Happy Birthday, Timmy!" at the end of the episode.
This episode was produced one year after NSYNC confirmed their departure after their performing hiatus back in 2002. Nickelodeon retired Chip Skylark from the show after his final physical cameo in "Momnipresent". His voice actor and former NSYNC member, Chris Kirkpatrick, slowed down his popularity during that hiatus, causing Chip's appearances to be lacked as a background cameo.
This is Chip Skylark's birthday too, which could be the reason he returns and the reason he remembered Timmy's birthday since "Boys in the Band".
Apparently, Vicky remembers Timmy's birthday better than his own parents.
It's possible this isn't Crocker, as shown in Crocker Shocker, there are multiple people who look like Crocker.
In one scene, Timmy's nose appears pointed, as Cosmo and Wanda's, not rounded, as it usually is.
Timmy says that there's nothing in his room that can prove that it's his birthday, but right behind him, there was in the wall a calendar, written "my birthday".
Timmy already knows that he has until he is eighteen years old to keep his fairies, according to "Channel Chasers".
The irony in the losing fairies concept when growing up is that in Channel Chasers, it's stated that if one grows up and is too old to believe in fairies, they have to go away. But in this episode, it was treated as if Timmy turned a year older, he would lose them. Though in the end it was cast aside due to the usual nature of Timmy's parents and Vicky's cruelty.
In Apartnership, Cosmo and Wanda's anniversary is on the same day as Timmy's parents. In this episode, Timmy's birthday is on the same day as his parent's anniversary. However, Timmy's birthday is not mentioned in Apartnership, even though it was his birthday. Also, Cosmo and Wanda didn't celebrate their anniversary in this episode, even though it was their anniversary.
However, given the nature of Timmy's parents, it's very possible that it wasn't their anniversary and they forgot the actual date of their anniversary, celebrating it on a different day than the actual anniversary.
When Timmy says he will never lose his fairies the clown passes his house but the clown was supposed to go to Timmy's house.
When Timmy's eating his strawberry birthday cake from Vicky, the birthday cake does not taste like strawberry again, but tastes like chocolate.
Chip Skylark's shoelace doesn't have "Chip" written on it like usual.