I played as a pretty bad Slark lastnight:
http://dotabuff.com/matches/565977958Like Vibe said I'm liking going solo offlane (although my teammates seemed confused at first about that concept). I "wrecked" Chaos Knight in the laning phase as soon as I hit level 6 and even managed to sneak into their jungle and kill Enigma but it kind of just went downhill after that. Medusa literally afk farmed ancients for a half-hour and was level 11 while we were all ~14 trying to team-fight (I had snowballed a bit and was 17). Zeus picked up a refresher and basically critically wounded me at the start of every teamfight and Earthshakers fissure managed to stun me a few times while I was in mid-air.
The only thing that saved us that game was Rubick stealing black-hole twice, my mopping up some kills and space creating (feeding from diving super deep), and Medusa managing to come online ~45 minutes into the game while we held off. Also, their Wraith King rage quit about halfway through.
What sort of item build do you think Slark should go with? I was going poor man's shield, to boots, to basher but I was considering going with yasha and then SnY or Manta for silences and extra dps on leashing. I went yasha to bkb my last game because I kept getting caught out and mass stunned/lightning bolted/chaos knighted.
Also, what do you think of afk, ancient farming Medusa?

The guy swore by it but it seemed iffy when he was behind in levels and items until he finally joined teamfights and farming lanes. Either way I'm off to watch the replay right now.