Yes, but.

One of the reasons Yvain posts there instead of here is because the standards are different; a post on LW talking about the problems with internet feminism would get a "hey, politics is the mind-killer," but on Slate Star Codex it's his blog and he gets to talk about whatever he wants to talk about. Besides content, there are presentation differences; Yvain has a jokey style that irritates some of the pedant crowd on LW, but engages more typical readers.

gwern also thinks the different branding has something to do with it; instead of being 'just another' LW poster, and LW having a scattered focus with many components that won't appeal to any particular reader, it's a clearly distinct site with a narrow focus. The average post quality on SSC is far higher than the average post quality of LW (note that Yvain has the second highest karma of any poster here), which makes it easier to recommend, because you're recommending Yvain specifically.

I think the comments on SSC are terrible relative to LW- the system is bad (without an inbox, upvoting, downvoting, etc.) which makes bad incentives (I'm nowhere near as careful commenting there, and have noticed that I'm much more likely to be snarky and negative) but also the commenters just seem dumber and less worth reading (but this may have to do with the increased focus on politics and decreased focus on self-improvement). But you don't share a site on social media / email it to others because of the comments, you do it because of the posts.