I guess I'm envisioning finding new content / islands through people linking to interesting posts or some functionality equivelent to retweeting. When you view these posts your client can then say 'give me that individual post that was linked / liked / retweeted by my friend please', but if you're not sufficiently networked with the person your client can't just say 'give me everything that randomer has ever said please.'
The mechanism of links / 'retweets' / likes could allow certain posts to 'go viral' and bring islands closer together, maybe.
Like you, I also like the ability to 'spider' my way across twitter myself (as though I was a web crawler), and find interesting things.. Like, look at a thread, look at the replies, look at the profiles of the repliers, see what they've been replying to, etc. However, I think I'm willing to sacrifice some of the ease of that experience to reduce the likelyhood of a google-butt emerging and embracing scuttlebutt, extending its functionality (by making it easier to find random content), then changing the protocol, then making the user the product again.
I'm not so worried about a google-butt that is just a proprietary and separate search engine application that makes content and people easier to find. I'm more concerned about a large-scale google-butt that is a proprietary patchwork-like client, makes the user the product (filtering content, promoting advertisements / more commercially valuable content, etc), or actively intervenes in the network with propaganda in a cambridge analytica style manner (leveraging its view of the entire network to see how successful its interventions have been.)
Leaning on ssb-ooo for spontaneous discovery is the best compromise between these two values I can think of... Perhaps we could also make some more voluntary mechanisms to allow randomers to discover each other in a controlled / more limited way. Or allowing clients to opt in to sharing their entire post history with spiders.
Or perhaps putting this limitation in just makes it a little bit harder to become a google-butt. Ugh, I don't know... It's a tough problem.