The characters for Shameimaru literally mean, in sequence, "to shoot (an arrow)" (or "to shine into/onto"), "command, decree, order" or "life" (or "hit/target" in the word meichuu (命中)), and "circle" (common name ending, usually seen in names of crafts and swords or similar weapons). Aya means "text, sentence, literature", and it's also the first character of "Bunkachou".
The name Shameimaru is derived from Sha-Mail (Shamēru → Shameimaru), which is text messages with photos, very appropriate for a fast-travelling journalist who takes pictures.
Aya owns the Bunkachou (文花帖), a tengu notebook gathering innumerable photographs and handwritten notes. Bun (文 - can also be pronounced as "aya") means "sentence, text", ka (花) means "flower, blossom" (or "pretty, cute thing" in a figurative sense) and chou (帖) means "notebook": therefore Bunkachou literally means "notebook of flowering sentences"- her record of interesting observations for Bunbunmaru Newspaper articles and pictures of beautiful danmaku or cute girls living in Gensokyo.
Aya is on less than good terms with some of the other characters. This is not necessarily because of her personality, but rather because of the news articles she writes about them, which are filled with as much of her own personal opinions as actual news. When she publishes things like "Reimu just seems to be a laid-back drunkard" in her newspaper, it's no wonder many other Gensokyo residents are less than thrilled to see themselves in the news. Nonetheless, that comes from her very inquisitive nature and a tendency to exaggerate events, rather than the desire to corrode other people's reputation for the sake of it. In fact, she has developed ethics and goes out of her way to pursue the truth, sometimes to a fault.
ZUN once commented that the gaming concept of Shoot the Bullet was around since the same time he created Embodiment of Scarlet Devil. Since such a game required a camera-using character, Aya was created specifically to fit that purpose.
In Mountain of Faith, Aya is the first stage 4 boss in a Windows game not to have some sort of gimmick/variation based on the playable character (i.e. Patchouli's different spell cards in Embodiment of Scarlet Devil, Reimu or Marisa in Imperishable Night, etc.)
Although Bohemian Archive in Japanese Red described Aya having black wings, you cannot see them in the artwork of Shoot the Bullet and Phantasmagoria of Flower View. This lead to confusion in many fan works, as many artists took liberties on this subject. Various theories have been made regarding the wings, and the most commonly accepted explanation is that Aya can magically hide her wings when they are in the way.
She is the first character in Touhou to originally appear in an artbook, then later in a game.