One might say that early Youtube was mainly thought of as a video pastebin that allowed (JS-assisted) hotlink-embedding into other pages. Youtube was to video as image-hosting sites like Imgur were to images. Which was important, in both cases, because not just video but even (HQ) images were hard to host yourself at the time, and also hard to send to other people without hosting them somewhere.

With both video and image-sharing sites, you didn't really expect the site itself to function as a social network that was worth "browsing." Rather, you expected the "front page view" to be an upload view; and from there, to take your uploaded assets and embed them onto a page to put them into proper context. And it's these webpages-that-contextualize-image/video-assets that you'd share links to, on forums and on early social bookmarking platforms (Fark, StumbleUpon, etc.)