Categorizing content by topic is something that has been implemented in many places, with mixed results. In the case of Reddit, topics are as much (and sometimes more) definition of a community, than of subject matter, and the content and its quality is dependent upon the number of contributors. Community content usually has a lifecycle, and eventually the forum drops in value. It's not something I wanted to mirror. Its not terrible, but it has been done and done.

Hubski is in large part designed with the purpose of gathering around personalities and interests, rather than topics. That's the experiment. The jury out on whether this is an improvement when compared to something like Reddit. But that's not my yardstick. I'm more focused on whether or not Hubski is interesting and rewarding, rather than whether or not it is an improvement on Reddit. In fact, it might not be easy to make the comparison when all is said and done. i.e. Are Twitter or Google+ better than Reddit? Depends on the expectations.

I implemented tags to provide a dimension of user-based grouping, whatever it might be. If a user wants to create a tag to subcategorize their posts, that's fine. If a transient event like OWS pops up, and users want to group their posts around it, that's fine. If users want to editorialize with them, that's ok too. Tags are also likely to be useful when I implement search and can improve recommendations. The tag is an optional color to be added to the post. Part of my reasoning for tags is due to the organic creation of hashtags on twitter. In the user/subscriber model of content curation, people wanted a way to group content, so they created one. Hubski doesn't have a search mechanism yet. But if it started with one, I suppose organic hashtags could have arisen to turn 'Hubski search' into a filter. One of the biggest problems with Hubski tags IMO, is not what they do or don't do, but the expectations that they bring.

As a means of subscribing to topics, Hubski tags are not very effective. If I wanted to support subscription to topics, there are obviously better ways to go about it. But I have spent a lot of time in topic-based communities, it's not an unsuccessful way to build forums. But I set out to try something different. Perhaps you are right, and having unequal dimensions of affinity is deleterious to this effort. Maybe we should eventually drop tags altogether. That's an idea I am willing to entertain. Probably more than expanding upon them. In fact, perhaps the best way to go about this is just to make an effective and interesting search/recommendation engine which users can leverage in their own way.

At this moment, I am going to roll out this ignore-by-tag for external posts, which mirrors the ignore-by-user for external posts. I'd like to see how that works, and to what extent it is used. I'm working on PMs, and that is my current short-term goal. I want to roll that out, and let it set in. Barring some unforeseen demand, I'd like to decide the future (and clarify the goals) of tags then.