I've started the cleanup process for industry, anyone else care to join in?
I've added these three tags to the list at http://meta.stackexchange.com/questions/128315/the-great-stack-overflow-tag-question-cleanup-of-2012 (I'd also make the slight suggestion that this be closed as a duplicate of that, but I wouldn't say it's necessary).
That said, here are my thoughts about the three tags:
blogs - I looks like this is the worst offender, with a great deal of not constructive content (lists of blogs, or "how do I write a good technical blog"). It should be removed in these cases as well as close-voted for "Not Constructive" and possibly flagged for moderator attention if there isn't enough traction on the question to get it closed through close votes alone.
However, if the question is a legitimate programming question about a blog engine, please tag it with the appropriate blog engine-specific tag (Drupal, WP, etc). We more than likely have them now. If one doesn't exist, then flag for moderator attention (or comment at us) and we'll add the appropriate one.
startups - These mostly look to be about business concerns. I would target this tag for total removal, and most of the questions fall in the "Off Topic" category. Please vote to close and flag as appropriate.
industry - These seem to be related mostly to process. Again, most of these questions are Off Topic, please vote and/or flag accordingly (the same caveat about P.SE applies here).
Overall, if there is no tag that can be applied while removing these tags, I would tag it with language-agnostic. I'm not saying it's a garbage dump, but these questions are language agnostic, and they are fodder for closure/deletion, so we wouldn't be polluting the tag, as we'd be cleaning up whatever we are adding to the tag in the process.