[AT&T Samsung Galaxy S 4 Q&A, Help & Troubleshootin] SprintGalSII:
It was a Feature o the S3, Note and Tab 10 that Samsung removed

The Edge Slide Zoom feature, as some call it, was actually a feature that Samsung "quietly" put on then took off, partially. (so quietly, I have yet to find a name for it anywhere on Samsung's website, in documentation, and if you contact Samsung Tech Support, either via Chat or at the "Dedicated Galaxy Support Phone Number" you will find they don't even know about it. In fact, I once got into a heated dispute with a "Dedicated Galaxy Support ""TECH"" " because he insisted I had loaded 3rd party software and they could not support me on it. I had to escalate to a supervisor, who confirmed the underling's claim until I firmly asked him to go get a S3 and I'd prove to him it was not 3rd party.)

It was on the S3, Note II, and Note 10.1 Tablet. Sprint removed it from the S3 with the February OTA release of MA6, which I refused until I got so fed up with Sprint, that I switched to AT&T. Much to my chagrin, the AT&T current release still has it. I bought 2 S3s, but got an S4 for myself. Unfortunately the S4 doesn't have it, so I'm hoping someone on here will develop it, like the user below references, except on the S3. Sprint removed it from the Note II in the last update. I don't know about other carriers, and I don't know about the Tablet. I'll be at the AT&T store later this week and will check, and report my findings.

I found it to be so useful myself, it was what pushed me over the edge to renew a 2 Year Phone Cost Subsidy agreement with Sprint, replacing a "Rooted" SII that finally was working, after I got so fed up with Samsung dragging its feet on releasing their last update.

Here are links to others who discuss it, and the only link I've found where Samsung even acknowledges it exists.

CHECK OUT HIS/HER DESCRIPTION:

[MODs][MD4][TW roms][DeOdex] Slide Zoom/ APM/ and APM with Hold Menu to kill App

"Because I love this feature, I port it to every new rom that comes out. It was originally from loserskater. This is slide zoom or edge zoom whichever you prefer, created for Sprint stock touchwiz deodex 4.1.2 MD4 only. It may work for others but i havent tested that at all. Remember to do a backup first."

http://xdaforums.com/showthread.php?t=2253747&highlight=edge+zoom

Here is the Note reference to it, which is at best obscure, if not about the worst possible description of the feature I could imagine. It would appear the writer never took the time to try it, so to be able to describe it more accurately, something like "Touch then Slide any finger along the edges of the screen (whether in Landscape or portrait, left edge (for "lefties") or right edge) then Slide Up to zoom in, slide down to zoom out.)

Instead, here is their description, in section Enhanced User Experience:

"Internet: Slide your thumb from the left or right edge to zoom in and out"

Pitiful, don't you think? No wonder people didn't even know it existed. In fact, I at first thought it was a bug, until I tried "reproducing it" to be able to report it, and then found it was entirely reproducible, so reproducible as to be something I trained myself on in about 5 minutes, and loved it ever since.

The big reason, ONE HANDED PHONE USE, ONE FINGER FULLY USER CONTROLLABLE ZOOM LEVEL.

It is far superior to "pinch to zoom" which requires Two hands, to hold the phone in one and pinch with the other, and two fingers. IT was and is INGENIOUS.

My guess!! Samsung had to come up with something to counter Apple's lawsuit for "pinch to zoom" and did, and it was awesome. WHen they lost the suit, but the penalty was "pocket change" for a company of their magnitude, they dumped it. Like adding a physical Home button to a touch screen, they seem to have this whacky nervousness about being too different from Apple. THe Home button is an absurd idea. I fumble the phone every time I have to press it. Not to mention the fact, I know with every press I am imposing salt from my sweaty thumb into a switch, (salt -> metal = corrosion DUH!!!!) which is by far the dumbest idea even Apple could have had. I digress.

Anyway:

http://www.samsung.com/us/article/galaxy-note-10-1-update