Add link to an old TTMIK video.

[minor]

voussoir.net/writing/beginner_bubble/beginner_bubble.md

@@ -94,7 +94,7 @@ Contrast that with someone who shows, say, how to build a house from the ground
 
 Every couple of weeks they publish a video reminding you to buy their books.
 
-TTMIK's best product is undoubtedly Iyagi, a now-defunct podcast which totaled 145 episodes of pure, no-English, normal-speed Korean speech plus full transcripts. At one point, all the episodes were freely available and I downloaded them. Now they're behind a paywall, because TTMIK realized that their podcast from 8-10 years ago is of higher value than the hours and hours of video they make now.
+TTMIK's best product is undoubtedly Iyagi, a now-defunct podcast which totaled 145 episodes of pure, no-English, normal-speed Korean speech plus full transcripts. At one point, all the episodes were freely available and I downloaded them. Now they're behind a paywall, because TTMIK realized that their podcast from 8-10 years ago is of higher value than the hours and hours of video they make now. Their [old videos](https://www.youtube.com/watch?v=cP55GAFNCx8 "Princess Service") are pretty hilarious, too. As always, it's the business that spoiled the product.
 
 [Duolingo](https://www.duolingo.com/) has a [reputation](https://old.reddit.com/r/languagelearning/search?q=duolingo&restrict_sr=on&include_over_18=on&sort=relevance&t=all) for people using it to study on a daily basis, sometimes for months or years, without making significant meaningful progress. Yes, we can blame the learners for only using a single resource, and only using it for a few minutes a day. But Duolingo's reputation in this regard far overshadows any similar examples I can think of. There's clearly something about Duolingo's formula that encourages the learner to feel as if they're being productive without actually helping them out of the bubble. Part of that comes down to their advertising, and part of it is their UI's positive tone and encouragement without reminders to study harder with other resources too.