Don't take it so literal. It translates to "She is someone." This is trying to intertwine vocabulary and sentence structure. You probably will never say something simple like "she is someone!" but you are practicing syntax and vocabulary.
She is someone important = sie ist jemand wichtig
I think the question is whether the German "Sie ist jemand" has the same connotation as the English "She is someone" (i.e. she is an important people), even without adding "wichtig"/"important." It would make sense for it to have this connotation, since the literal meaning of "she is someone" is not very informative.
I don't know if it could be of any help, but in my mother tongue language (Czech) we still say "je to niemand"(=he is niemand) - we really use the word "niemand" (historical reasons - Austria-Hungary and then Second world war). It has the social connotation, thus it means the person is not important. (We also have Czech sentence for "he is somebody" and it also has the social connotation, but we use only Czech terms for it).
Wiktionary seems to agree.
About the only difference I can discern is that irgendwer seems to be more colloquial (umgangssprachlich).
dict.cc lists the following for "anyone":
"sie ist" = "she is; ""sie sind = ""they are" (1st letter of sentence capitalized);
"Sie sind"= "you are" (Formal version of you singular or plural - Always capitalized)
http://german.about.com/library/anfang/blanfang02.htm German Personal Pronouns http://german.about.com/od/grammar/a/Germanyou.htm http://german.about.com/library/blcase_sum2.htm Cases for Pronouns
"Ich liebe sie"; "I love her. " or "I love them."; Ich liebe Sie. "I love you."
I wrote "sie ist nemand" and that was correct also... why?
Single-letter mistakes that do not result in a real word are often ignored as typos.
Since nemand is not a word in German, it assumes that you did not write that deliberately but that you intended to write the correct word jemand and made a single-letter mistake.
You usually use "someone/somebody" in positive sentences and "anyone/anybody" rather in negative sentences or questions.
If used in a positive sentence "anyone" has the meaning "an arbitrary one" which exactly is not meant by the German "jemand". That would be "irgend jemand".
In a way the two sentences are exact opposites of one another:
"Sie ist jemand" = she is someone (i.e. a celebrity or a VIP)
"Sie ist irgend jemand" = she is anyone (i.e. could be everyone, she's nothing special).
yes. All of these words are indefinite pronouns (the name stems from the fact that they give some kind of number, but a very unclear (indefinite) one).
"anyone"/"anybody" and "someone"/somebody" both translate to "jemand" in German. Therefore it is a difficulty for German learners of English when to use which one.
"no one"/"nobody" is "niemand".
Does anyone else think this is a clumsy sentence? "She is someone" would make me reply, "someone what?" I'm guessing the implication here is "She is someone (important)", but to a native English speaker, the "someone" in this case would be capitalised to show that "someone is important". Sorry, this sentence just bugs the crap out of me.
That would not be very common. We would say. "She is someone." You are correct that in English negations we often use anyone and it could also be used in a question. Certain expressions lend themselves better to one or the other translation. http://dictionary.reverso.net/german-english/jemand
It is anyone in questions or negatives. http://dictionary.reverso.net/german-english/jemand