As someone who spent way too much time obsessing over this stuff, this is awesome and very promising.

One reason I'm not happy with traditional spreadsheets is that there's no non-hackish way to implement "tagging" (as in, hashtagging) a given row. You can create a "tag" column for storing "tag strings" (all the tags that have been applied to this row, delimited by say comma) and then filter by instr or some regex, but it's inconvenient.

Haven't fully checked out the features of TreeSheets yet but I imagine it would be quite suited for this purpose? Is it possible to do a search for all the rows whose 'tag' column's value includes as a member (not: contains as a substring) a particular tag?