The data tag has quite a few questions (>250), but it seems to me the tag is redundant. (It also has no tag wiki, which is usually a sign, at this stage in the site's life, that the tag shouldn't exist.)
Many of them are better covered (and often already tagged) as dataset, database etc. Questions about how to manipulate and transform data in some way -- say, interpolating it -- would be better tagged according to type of transformation, e.g. interpolation.
It would be quite a bit of retagging / tag deletion work to get that done. What do people think?