Yesterday I went swimming and thought about tags the entire time. Don't think there aren't times that I click on the tag field and think: "WTF should I tag this as?!" Some creative tension is a good thing. Too much is a bad thing. I admit it is debatable. To me, tags represent more than the name implies. They have editorial, subscription, grouping, creative, and temporal (i.e. trending) components, and I'm thinking on these. If tags do change, they need to bring an improvement measured in terms of all these components, what users want to do with them, without breaking, or encouraging gaming of them. And, they also have to be weighted against current content management. Following a tag means that you get a post from anyone that used that tag (barring ignored users). It's a huge effect. Yeah, we can have that tag thread soon. But I need a swim or two more first.
"Tech" and "Technology" on the other hand have a lot of overlap by definition, and a little overlap with, say, "coding" and "gadgets" and "3d printing." With user following, you have affinity. With tag following, you have taxonomy. Affinity is the subject of poetry. Taxonomy is the subject of doctoral theses. How are you doing the recommendations? Just thinking aloud, but it seems to me that if whatever analysis you're doing can "fuzz" tag boundaries the way it "fuzzes" your recommendations, if I subscribe to "#tech" and the commenters, sources and vote profile of "#technology" is similar, I should automagically get a few, some or all "#technology" posts as well. The onus should be on the system to provide the user with content, not on the user to determine the appropriate tag for submitting or subscribing. Take it one further - allow multiple tags, but give each succeeding tag half the weight of the previous. If I tag a post about Rupert Murdoch's twitter feed with #business, #media and #murdoched, anybody who subscribes to any of those three tags should get it in their feed. However, since it was tagged #media second, it should be half as likely to end up in someone's #technology feed than if it were ranked #media first. This gives the user an incentive to be thoughtful about his tags, rather than scattershot - by the time you get to the fourth tag you have 12% the influence of the first tag and by the fifth tag you're in the noise. Until, at least, you have several tens of thousands of users and an equal number of tags, and then that statistical noise becomes more relevant. Eventually, a solid subset of "tags" will build... but if people start tagging content with a new phrase ("#occupywallstreet") it begins "trending" just like a twitter hashtag. I'm no coder, but here from the cheap seats it seems like an approach that doesn't require tending, has room for growth and works the way I think you want it to work. Now go swimming.
Yeah, more swims.
Aren't they both content management? If I found Robert Silverberg because I love science fiction, and then read "Book of Skulls" which is anything but, that doesn't mean I've transferred my love of science fiction into a love of Robert Silverberg. Likewise, "books about monastic orders" would include "The Name of the Rose" as well as "Canticle for Liebowitz" and "The Book of Skulls" which gives you three different authors - I can follow Umberto Eco and Robert Silverberg without worrying about how they're connected or what impacts they have on each other. Likewise, following UmbertoEco is likely to lead me to Carl Hiassen or Milan Kundera much quicker than #MonasticOrder is. Meanwhile, #Roadtrip would include "Book of Skulls" but neither of those authors and neither of their books - but it would lead me to "The Road" and "Zen and the art of Motorcycle Maintenance" where I can accept or reject Robert Persig and Cormac McCarthy on their merits, not their relatedness. Should I decide to follow Cormac McCarthy, it's going to lead me different places than if I follow Robert Persig, and that's appropriate. The two functions are intertwined, they do not compete. I think you see it as an "either/or" proposition while I see it as an "X/Y" proposition. As far as "finding their own uses" I think you'll discover that those uses have been found. "Tagging" is not new, is widely accepted, and has a pretty broad featureset that has been adopted across many industries. It just seems to me that the uses your users have found don't entirely jive with the ones you want them to find. ;-)
I'm just saying that's part of what I am weighing in any possible tag redesign.