In football, what is a slot back?

A slot back is basically a slot receiver who lines up in the backfield.

This page is pretty instructional.…

It says:
"The flanker can also become a slot receiver or slot back. If he’s positioned between the split end and a tackle, his name changes. The coach can take out a tight end, making a slot back the third receiver, attempting to create mismatches with the defense. But even in a standard set that includes a tight end, the receiver can line up between the split end and the tackle and be called a slot back. This gives him a few steps running start before the defender can smack him one."

Wikipedia says a slot back is:
"A receiver lining up in the offensive back field. Canadian and Arena football allow them to take a running start at the line. They are usually larger players as they need to make catches over the middle. In American football slot backs are typically used in flexbone or other triple option offenses while Canadian football uses them in almost all formations."…

What are the best "value for your money" restaurants in Philadelphia?

My wife and I, as well as our friends, love to eat at the Sang Kee Noodle House Asian Restaurant.  There are several locations in Philly but we most often visit the one in Wynnewood on the Main Line.

The Asian food is consistently delicious, reasonably priced, and served with quickly, efficiently, and pleasantly by an excellent staff.  You will be treated with kindness when you enter, fed well while you're there, and leave completely satisfied … eager to return next time.

BTW, try to avoid times when it will be very busy like Friday and Saturday evenings.

Is the downvote-answer feature necessary on Quora?

Yes.  Without downvoting, I think you open Quora up to non-constructive answers which weaken the strength of the site. See What are good and bad reasons to downvote answers on Quora? That question has a number of answers that get at this point. That question and its answers also support the secondary point that Justin Bishop is making — which I agree with — that unfair/unreasonable downvoting is demoralizing.

Does physical printing of Chinese text cost more than of English text?

While there's no longer a direct physical correlation between the the number of characters in a font and the cost of print, be aware of the cost of the font itself – and in some cases the RIP (Raster Image Processor) that's required to turn the vector information from a font into a high-resolution bitmap image suitable for printing.

Some Chinese and Kanji fonts are extremely expensive.  Printing companies have to pay vast sums in licensing fees to be able to process them. As long as you choose an unlicensed/shareware type font you should be fine.

What conferences or industry events should I attend if I want to be well ahead of trends in software, web services, security, machine learning, etc?

No offense, but the cutting edge of research in those fields is some intense stuff.  Because it's so new, there hasn't been a "layman's explanation" yet, or even a clue as to how that technology could be applied to the real world.  In machine learning, for example, you'll get what are essentially math or statistics papers with pages of proofs and derivations about minimization of some bizarre norm for matrices too large to fit on disk (or whatever).

It isn't until someone takes that, understands it, and applies it to a problem that everyone goes "aha!  this technique is valuable to solve this type of problem."  By then, the secret is out =)

That said, some conferences that focus on applications (and might have more readable papers) are:
WSDM (…)
OSDI (…)

edit: just FYI, the question text changed a while after I submitted this answer.  it used to be about conferences for a non-technical person interested in bleeding-edge machine learning.

What songs have the same meter of many of Emily Dickinson's poems?

"Because I could not stop for Death" is written in what is called common metre: a four-line stanza with syllables of 8, 6, 8, 6, and with all lines in iambic feet (unstressed/stressed). A good many hymns, e.g., "Amazing Grace," are written in this meter. As has often been pointed out, the hymns that Dickinson grew up hearing were probably the stimulus for her rhythms.