Yes, a tag cleanup effort would most definitely be advantageous.
I initially thought about making that part of the current cleanup effort, but decided against it because I thought it might be too much for one contest. But you're right, we could use a tag cleanup effort.
Our tags are not very organized at the moment. I think the main reason is that we started as a 1.0 site, and not going through the normal Area 51 process resulted in us not putting too much thought into some of these things. I've slowly been trying to organize the tags as I find them, but there's still a lot that need to be cleaned up. Here's the current list of tag synonyms.
If you find any other tags that you feel should be deleted, explained further, or are synonyms of each other, please post it on meta, as you've done here. Alternatively,
Users with more than 1250 reputation and a total answer score of 5 or more on the tag, can suggest tag synonyms. Users with a total answer score (total upvotes minus total downvotes) of 5 or more on the tag, can vote for tag synonyms. Suggestions will be automatically approved when they reach a score of 4, and automatically deleted when they reach a score of -2.
After we finish the current cleanup contest we'll think about how we can implement something similar to clean up the tags. Feel free to post any ideas you have on how we can implement this.
As for your tag synonym suggestion, I agree. I think incorporating and incorporation are essentially the same thing. Even if they're intended to have different meanings, I think the two are so similar that it would just cause confusion to keep both of them. I'll give it a few days to see if anyone disagrees. At the end of the week I'll create a synonym pair for these.
I think the dba tag is sufficiently different from the other two that we can keep it. Doing Business As is normally used by sole-proprietors which are not incorporated.
Thanks for pitching in to help the site :-)