What is the difference between these two positions in the game today ?

very little is the truthful answer. one small difference is that 7 is more likely to perform the dummy half role if the hooker is not there/tackled etc, and more likely to be able to swap into the hooker role - ie: abrasive, able to scoot, decent pass off the deck etc, as well as being the playmaker on 1 side. The 6 generally needs a bit more of a kicking game, and may be a bit more fragile defensively (benji). if a player is more of a kicking pivot type playmaker, he would probably play 6, and sometimes move into 7 (sean johnson, stacey jones sean long danny mcguire etc) whereas if he is more of a low-centre of gravity quick-footed agile wee ball player he would probably gravitate towards 9 with the ability to cover 7 too.... thomas leuleai, michael monaghan, rob burrow etc.

This is just my take on it - i have no issues being shot down if somebody wants to add a bit more detail.

It depends on the system I'd say.

Some have them on different sides of the pitch, some have them on the same side both as receivers to link up. Looking at Wigan this past season for example, Green & Smith were typically the 2nd & 3rd receivers respectively with O'Loughlin as the 1st receiver, whereas another team would have their Scrum Half first receiver all of the time. The Scrum Half can be seen as more of an organiser whereas the Stand Off is a more off the cuff player, but some systems do have this the other way round, or not at all.

Yeah, there are differing ways and in the modern game they seem quite interchangeable roles. Traditionally a scrum half would be the shepherd for the forward pack and the stand off would run the backs but the hooker seems to do a lot more in modern rugby and guides the pack around more and more.

No difference at all. It's about striking a balance in your half-back pairing.

A lot of teams play one first receiver left the other first reciever right, the hooker now plays the traditional/old fasioned scrum half but then he won't hook the ball. I suppose that's what makes our game different to the other code, our players have to be versatile & adaptable. I dont know how I would have faired today as a winger, in the old days I just stayed out on the touchline & kept my shirt clean.

Scrum Half tries to create 1 on 1 opportunities/ miss matches for the forwards and the stand off tries to put the backs in to holes.
Or you could have split halves , one left of ruck one right of ruck were they do both.

Scrum halves tend to be about 5' 4" and stand offs can be up to 6' tall.

For me I would say that Stand offs tend to be more of an organiser and a good kicker whereas a scrum half tends to be more of a runner and takes the line on more

Like most answers: It depends.
Most teams now just play left and right, and either player could be in either slot.

The older way was to play scrum half at first receiver, closer to the ruck and so working more with the forwards, or to act as a link to the SO, who played wider and so more with the backs. Back then, the loose would also be more of a pivot and might play on the short side.

In a lot of ways, the left/right split gives you two scrum halves, with the fullback acting as the wide running stand off.

Leeds don't have a system. We just stick 3 or 4 on the pitch at the same time and see what happens.

As a few people have said, the most important part is to find a pair that work together

A perfect example is those two great Australian half back pairings of Wally Lewis & Alfie Langer and Peter Sterling & Brett Kenny

In the Lewis/Langer partnership, Lewis was the general who bossed the game while Langer had a more dynamic running game while in the Sterling/Kenny partnership it was the scrum half who was the general and the stand-off who was more off the cuff and dynamic. These two pairs complemented each other perfectly

(Of course Lewis could take the line on while Langer had a passing game etc but I am referring to the dominant role they performed)

The waters have got a bit muddier recently and the Cooper Cronk/Johnathan Thurston partnership for example doesn’t separate the roles quite so explicitly but the key thing is that all of the key skills and responsibilities are covered

A little unfair on the team and the coach there....Leeds run quite a structured system of Sinfield right, Mcguire left. There's a bit more play based around Burrow jumping out of acting half and a bit less of the [ifullback-standoff[/i role, but that's because Hardaker can't pass very well.

I was just being a tad mischevious with amount of playmakers we have.

Works though!

Not much difference between the roles in reality.

Paul Rowley played a strong tackling second rower (Craig Briscoe) at 7 in a game when it was raining heavily, he made 30 odd tackles right in the centre for an hour and then was replaced by Ryan Brierley who tore apart a beaten pack.

Just to show how cloudy the lines can be.