Occasionally I have done a search like this:
smirnov -[kolmogorov-smirnov]
to locate posts that mention a word that's likely connected to the tag, but doesn't have the tag.
The second post that it turned up, for example, appears to be a possible candidate for having the tag added.
I do this for a variety of reasons, but one is simply to add tags to posts where I think they need it so people can find them more readily, for example. (More selfishly it helps me locate posts I feel like answering at the time that I won't have found in previous forays with the tag.)
I was just doing this kind of search with the histogram
tag now, and added a few (not every post that mentions the word needs the tag however and I am sometimes left to ponder when it's reasonable to add and when it isn't. This post is not about that quandary).
It occurred to me that maybe there's some issue with specifically searching for missing tags and (sometimes) adding them in this manner.
It's not something I do all the time, just now and then as the mood takes me (usually after noticing what seems to me to be an important but missing tag on a post).
So is there anything out of order with that kind of behavior? Is it a good idea? A mix?
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Edit:
A big thanks to AndyW and gung for their insightful, helpful, high quality analysis, and useful links.
By way of summary so far -
there's a problem with doing it for a single tag on a large number of posts without consultation
even with a smaller number of posts, there's a problem with doing it on more than a couple at a time in quick succession because of the impact on the front page - so it should be well 'spread out' in time.