Some enthusiasts are still on Diablo III and they're not just messing around casually, but achieving crazy things -- for example Vajet, who has already reached a combined level of Paragon Level 2000.
Vajet is currently Paragon Level 1789 in Season 3 and his non-seasonal characters are at Paragon Level 1339. The experience he gained during Season 3 will be added to his non-seasonal heroes when the season's over, so that's when the official ladder will show his characters with Paragon Level 2000+. But technically, he's already at level 2003. His combined seasonal and non-seasonal experience tallies up to Paragon 2000+, which is absolutely crazy. Reaching level 1000 is quite the feat, even for veterans, but this basically means non-stop playing.
And what does Paragon Level 2000 mean in terms of raw statistics? It means that according to his profile he killed 15,374,712 monsters, 1,929,374 of those being elites. Paragon 2000 is the equivalent of 119,324,847,480,000 experience points and reaching Paragon 1000 eleven and a half times. And jumping from Paragon Level 2003 to 2004 requires 170,641,920,000 experience points.
Diablo3ladder interviewed Vajet and he mostly talks about how he managed to collect the combined experience points (you might think it's botting but that's not the case) required to Paragon Level 2000 this fast. It's worth reading if you're about to return to Diablo III when patch 2.3 hits and need some tips on efficient levelling:
Since patch 2.2 and it's including buff of Greater Rift experience gained, Greater Rift farming has been the most efficient way to get EXP. In Greater Rifts, bonus experience items and sets such as Hellfire Ring scale multiplicatively with the EXP gained which means you can gain more than three times as much wearing all of these items compared to a player who does not wear any of them.
However, these experience items and sets can't all be combined with the most powerful sets and items in the game. This basically means that in order to get the most experience you are depending on players who are playing with their best sets/items (in terms of damage) so that you can wear all the experience sets/items and play a support role.
Some classes like the Crusader and Monk are especially suitable to fill these support roles as they are very tanky and have a lot of offensive and defensive buffs.
Because of these group setups it became a habit that the support players come up with either trial or greater rift opener keys.
My strategy was to organise very fast and efficient farm groups where players playing classes like Demon Hunter (which are not suitable for support roles) would get a large amount of blood shards and items.
Unlike other players trying to maximise their EXP gain by wearing the full EXP item setup, I ran a reduced EXP item setup in order to make the runs faster and more rewarding for the DPS players. This way I never had a hard time finding people while the competition was struggling to find players that actually want to play with them.
That's pretty smart.