Given the Question and Answer pair, detect whether the answer is acceptable or not. Denote acceptable answer as "yes", otherwise denote as "no". An acceptable answer is consistent with the context in question, detailed, long, and uses general knowledge of English. Answers that are not definite and suggest a variety of options are not acceptable answers.

[EX Q]: Question: I am referring to someone who makes people 'buy' what he says and gets things done by them through nothing but clever speech something one can describe as crafty or beguiling, but not fraudulent. I pondered over con man and con artist for a while but those terms seem to hold a hint of crime, so those terms won't fit in. I am wondering if there is a more suitable phrase or word. 
Answer: Not quite a single word, but silver tongued probably fits.
[EX A]: yes

[EX Q]: Question: I debated with my peers that we can use the word emails when referring to more than one and it would be grammatically right. But most of them said since we don't say we received mails today, similarly we won't say we received emails . Quick advice please. 
Answer: Dan Bron's comment (above) that e-mail/email at its inception was treated as a mass noun is correctand so is Kristina Lopez's comment (above) that e-mail/email is widely applied today not just to the medium of electronic mail but to individual messages sent and received in that medium. For many years the technology magazines where I worked enforced a strict house rule: e-mail (and later email) referred to "electronic mail" as a mode of communication, and individual messages had to be termed "e-mail [or email] messages." But three or four years ago, the overwhelming weight of popular usage prevailed, and we began to accept the use of email as a singular noun that could take an indefinite article, and emails as a plural nounboth referring to individual messages. It is probably not coincidental that other forms of electronic communication receive similar treatment in popular (and some publishing) usage: a text and texts for "a text message" and "text messages," respectively; and an IM and IMs for "an instant messaging message" and "instant messaging messages" (as I recall, people used to avoid "instant messaging message" by conflating the technology with the individual message to produce "instant message"). At publishing houses, the proper handling of "an e-mail [or email]" versus "an e-mail [or email] message" remains a house style issuethere is no universally agreed-upon preference. If you are beholden to no one's style guide, you are free to use the wording that you like better. But the overall tendency, I believe, is toward accepting an email and emails as collapsed forms of "an electronic mail message" and "electronic mail messages.".
[EX A]: no

[EX Q]: Question: I keep writing dataset. Is that correct, or should I write data set? 
Answer: As @mmyers notes, dataset does not appear in any dictionaries. However, there are 172 incidences in the Corpus of Contemporary American English, and all but a handful are in the "academic" section, representing formal academic writing. Its lack of appearance in dictionaries is probably because it is a fairly new coinage, the two examples from the Corpus of Historical American English are from 2001. Nothing from before then. Interestingly, the British National Corpus has 51 incidences, dating from the 1980s to the mid 1990s.
[EX A]:
yes