In the anime, when the Pacifista was locking onto to Usopp for its next attack, its bounty detector labeled him as Sogeking, even though he was not wearing his Sogeking mask (though his nose or the Kabuto could have given him away).
Although it is a fact that the newspapers (2 years later) managed to recognize Usopp, as he was labeled "Sogeking", proving the Pacifistas have the capability to recognize him.
Usopp's personal jolly roger (post-timeskip) as detailed in the One Piece Magazine.
Usopp's shadow in Zoro's wanted poster.
In addition to the Straw Hats' jolly roger, Usopp also has one of his own, like all the other members of the crew. The flag was first seen when Luffy asked him to design and paint a Jolly Roger for the crew. Though it was supposed to reflect everyone, Usopp designed his own jolly roger as their symbol, reflecting his delusions of captainship. It has Usopp's nose, bandanna, a star, and a slingshot for a cross-bone. Usopp's design was immediately rejected.
Usopp has a second personal jolly roger after the timeskip. In this version his skull is seen on its left side with Usopp's new hat, headphones, and his curly hair tied back. The Kuro Kabuto is seen on its side in the background.
Usopp can be seen in the corner of Luffy's former wanted poster and Zoro's former wanted poster. In Luffy's, he is simply viewed from behind. In Zoro's, his silhouette is faintly seen through the smoke in the background of the poster doing his Crocodile impersonation. However, in the anime, the latter was cut out of Zoro's poster most likely due to the fact that it is not easily visible and was thus overlooked. It was later corrected in Episode 152 but omitted again in the second bounty poster. It is unknown if he's seen on Luffy and Zoro's actual wanted posters.
It is possible that Usopp's long nose was inspired by the fairy tale "Pinocchio", as Pinocchio was a wooden puppet whose nose grew longer whenever he told a lie.
Usopp's name is possibly based on "Isoppu", which is the Japanese pronunciation of Aesop, the ancient Greek fabulist. Considering that uso means "lie" in Japanese, the name Usopp can be taken as a portmanteau name between uso and Isopp, since Usopp is both a liar and a storyteller. The name is also a Japanese pun in that saying "Ore wa Usopp!" can mean either "I am Usopp!" or "I am a liar!" because Usopp's name is written using Katakana characters and not Kanji.
In regards to his alter-ego, Sogeking is a play on words as the Japanese word for sniper is "Sogeki".
Usopp's personality could also come from The Adventures of Baron of Münchausen, who said he had traveled around the globe on a cannonball, a lie Usopp himself said in episode 19, though no one gave any attention.
"The Boy Who Cried Wolf" is a story of a boy that often tells lies of an impending wolf attack in order to gain attention, much like Usopp lies of imminent pirate attacks. When the wolf actually did arrive, no one believed him. This story was written by an author known as Aesop. The word "uso" means "lie" in japanese. It is possible these two instances are the influence behind Usopp's name.
Ironically, most of the tall tales he told Kaya have came true at some point during the Straw Hats' voyage. These include meeting a giant goldfish (as the crew was leaving Little Garden) fighting against a giant mole (against Miss Merry Christmas during the climax in the Alabasta Arc), meeting dwarves (when Robin and Usopp were captured by dwarves in Green Bit) and being a captain (as he is called by all the toys and dwarfs when he frees them on Dressrosa)
Despite being the weakest crewmate (according to Oda), Usopp is the fourth crewmember to awaken Haki behind the Monster Trio.
He, Luffy, and Sanji claim to have never been sick, and thus do not know what it feels like.
Ironically, despite being a coward, Usopp has no fear of spiders as in seen in the Jaya Arc. He even picked up a tarantula and petted it while the usually much braver Sanji jumped into the bushes at the mere sight of the arachnid.
He is the one who introduced the rubber band to the Skypieans.
Kappei Yamaguchi, Usopp's Japanese voice actor, came up with the notes to the Sogeking song. Oda provided the words and then asked him to develop the notes himself. Kappei also stated that the Sogeking song is the most requested song for him.
Sonny Strait, the FUNimation voice actor for Usopp, has stated several times during the FUNimation DVD commentaries that Kappei Yamaguchi is his favorite Japanese voice actor, saying that whenever he listens to Kappei's performance in recording it is like he is saying "Top that American voice actor!".
In the 5th Japanese Fan Poll, Usopp was voted the thirteenth most popular character in One Piece.
Skypiea has a theme park dedicated to Usopp called "Rubber Band Land". It has a drawn profile of him on the overhead sign and a statue featuring him as a muscular warrior, complete with a spear.
Usopp might be somewhat based on the Japanese mythical species tengu, who were said to have long noses and habits of tricking people. Kin'emon even referred to him as a tengu.
↑ 7.07.17.2SBSOne Piece Manga — Vol. 69 (p. 66),
First fan question: Oda-sensei, I have a question. Please tell me the current profiles (birthday, height, age) of all of the members of the Straw Hat Pirates! Second Fan question: Oda-sensei! Please tell me the order in which the members of the Straw Hat Pirates joined the crew! I'm really grateful!
↑SBSOne Piece Manga — Vol. 15 (p. 90),
Fan question: Oda-sensei!! I've been thinking about this a lot... what are Luffy, Zoro, Nami, Usopp and Sanji's birthdays? Tell us!!
↑SBSOne Piece Manga — Vol. 79 (p. 186),
↑SBSOne Piece Manga — Vol. 10 (p. 46),
Fan question: I wanna know the height of all five. Nami's really cute.
↑SBSOne Piece Manga — Vol. 37 (p. 46),
Odacchi-sensei. I'm super x2 curious about something! And that is... whose nose is longer, Usoop or Kaku? Plus, Odacchi-sensei, it's not very nice to draw people with artificial nodes. Damn is it long.
↑SBSOne Piece Manga — Vol. 45 (p. 188),
Fan question: Luffy's favorite food is meat. What about everyone else on the crew? And you yourself, Oda-sensei?????
↑SBSOne Piece Manga — Vol. 73 (p. 144),
Fan question: I was looking up trivia on the Straw Hat Pirates, and I found that although they've all been given a favorite food, I can't find anything about their least favorite. So what are each of the Straw Hat Pirates' least favorite foods?
↑SBSOne Piece Manga — Vol. 84 (p. 150),
Fan question: Oda Sensei!! Please tell me who from the Straw Hat Pirates likes ice cream, and who don't?
↑SBSOne Piece Manga — Vol. 79 (p. 142),
Fan question: In the Straw Hat Pirates, Sanji is obviously the one who is the best at cooking, but who else is good at cooking? What is everyone's speciality dish?
↑SBSOne Piece Manga — Vol. 38 (p. 146),
Fan question: Odacchi! I read One Piece! And laugh! And cry! I'm such a huge x(infinity) fan! So, I have a question for Odacchi and the Straw Hat Pirates! There are Spring, Summer, Autumn and Winter Islands. Which is everyone's favorite?
↑ 28.028.128.2SBSOne Piece Manga — Vol. 40 (p. 66),
First fan question: Hi there, Odacchi! I've wondering about something you might be able to answer for me! Since Chapter 334, Nami's been wearing the same tanktop with a 3 on it. What does it mean? Second fan question: Hello, Oda-sensei. If you have specific colors for each main character of One Piece, please tell us what they are. Second fan question: Hello, Oda-sensei. If you have specific colors for each main character of One Piece, please tell us what they are. Third fan question: I have a question!! If Chopper has such a splendid blue nose that he can tell where his crewmates are at any time, what do all the members of the Straw Hat Pirates smell like? Does Luffy have a rubbery smell?? Let's ask Chopper.
↑SBSOne Piece Manga — Vol. 48 (p. 26),
Fan question: Hello, Odacchi! I have a question; will you hear me out? ...Oh, you will? Thanks! Here goes. In the song the Straw Hat Pirates sing called "Family", they have a line that goes "We're not acquaintances, we're not friends, we're family". If the Straw Hats really were an actual family, who would be the dad, and who would be the mom?
↑SBSOne Piece Manga — Vol. 20 (p. 26),
Fan question: Fan question: Oda-sensei, out of the 5 crew members Luffy, Zoro, Usopp, Nami and Sanji, what animals do you think they most resemble?
↑SBSOne Piece Manga — Vol. 56 (p. 164),
Fan question: Nice to meet you, Oda-sensei. I have a question. If One Piece was set in the real world, which countries would the nine Straw Hat Pirates come from?
↑SBSOne Piece Manga — Vol. 59 (p. 96),
Fan question: Hello Oda Sensei~! Out of the blue but can you write what is inside luffy's head? oh and your head too--. my friend's head is half pervert and half games.
↑SBSOne Piece Manga — Vol. 60 (p. 206),
Fan question: A question to the Hana Hana no Mi user, flower loving Robin <3. Which flower would suit each of the Straw Hat Pirates? Sister Robin can go with a flower she likes <3 by I like cosmoses.
↑SBSOne Piece Manga — Vol. 66 (p. 162),
Fan question: Hello Oda-sensei! In volume 62 when Sanji meets the mermaids and blows a shower of nosebleed, Chopper was saying his blood type was "S", but that sounds really different! What are the other blood types? If it is okay with you, I would like to know the blood types of all the Straw Hat Pirates!
↑SBSOne Piece Manga — Vol. 67 (p. 182Fan question: In chapter 654, Chopper turns down Nami's invitation to join her in the bath, saying "I wiped myself down the day before yesterday", right? Is it because he's a boy? Or a fruit user? Or maybe... because he's an animal? I'm also interested in the bathing information for the rest of the Straw Hat Pirates.).
↑SBSOne Piece Manga — Vol. 70 (p. 124),
Fan question: The crew's hair has to grow out on those long voyages, right? Does someone give the rest haircuts? Nami or Robin, perhaps?
↑ 37.037.1SBSOne Piece Manga — Vol. 72 (p. 46),
First fan question: It seems that Trafalgar Law, in the midst of his alliance with the Straw Hat Pirates, gives them some nicknames. What are all the things he calls the various members of the crew like Zoro and Franky? Second fan question: If the Straw Hat Pirates were different prefectures of Japan, what they would be? For example, would Nami be from Ehime, I'd love to hear from you!
↑SBSOne Piece Manga — Vol. 74 (p. 126),
Fan question: I would like to know the Straw Hat Pirates' bed times and wake up times!
↑SBSOne Piece Manga — Vol. 76 (p. 42),
Fan question: If the Straw Hat Pirates were not pirates, what would their careers of choice end up being? Please tell us!! (Though I bet Sanji would still be a chef......)
↑SBSOne Piece Manga — Vol. 85 (p. 78),
Fan question: Who is the fastest crewmate when they run a 50-meter race?