First, let me congratulate the developers for shipping Hook. I am astonished to discover this app, because I proposed essentially the same idea in a discussion on the Journler web site a few years ago. The fact that someone else independently had this idea and implemented it proves that I am not the world’s biggest nerd—there are at least two of us!
Being the nerd that I am, I already have a well-developed personal knowledge management system, and I already have ways to link anything to anything else. The promise of bidirectional links is enticing, but not enticing enough to convince me to lock myself into Hook. However, I would be more likely to jump onto the Hook bandwagon if there were more ways to visualize links in Hook.
One way to improve the visualization of links that would be relatively easy to code is what I will call a “Journler-style hierarchical view”. The Journler app (which is now abandoned, but was a classic in its time) had bidirectional links like Hook, so that each item in Journler displayed a list of the other items that linked to it, but the list was an expandable hierarchical list. Any item in the list that was also linked to other items had a little triangle icon next to it; when you clicked on the triangle, a new indented list would drop down (outliner-style) below the item showing all the other items that linked to that item. This was a simple of way of visualizing and navigating the network of links between items.
Another, more complex, way to improve the visualization of links would be to implement an automated network graph visualization of links, similar to PersonalBrain or TiddlyMap.
Either of these ways of improving the visualization of links in Hook would likely be enough to convince me to lock myself into the app. (App lock-in is one of the trade-offs of using Hook. The benefits of using the app have to be great enough to justify the lock-in, and better visualization of links would tip the balance for me.)