Application support is limited, adding OpenType Features involves more work, most fonts don’t really need them.
The ligature features use many → one substitutions, so e.g. f + f → ff ligature.
Stylistic alternates (salt) can use one → one substitutions, but they require manual input, which is inefficient, but very flexible as the user can decide which letter form to insert. One glyph has a lookup table for several other forms to substitute for that glyph — the user has to choose from a dialogue presented by the application, which Stylistic Set to use.
} lookup StylisticAlternates {
sub asterisk -> [asterisk asteriskmath uni2051 uni2042 uni203B uni273B];
sub plus -> [plus uni2795 uni271A-uni271C uni2720];
sub at -> [at uni2121 uni213B uni260E uni260F uni2709];
sub copyright -> [copyright uni2117 uniF000 estimated uni2139 uni2638];
sub multiply -> [multiply uni2715-uni2718 uni274E];
sub dagger -> [dagger uni2620 uni2622 uni26A1 uni26B0 uni2690];
sub daggerdbl -> [daggerdbl uni2623 uni26A0 uni2621 uni26B1 uni2691];
sub bullet -> [bullet uni204D uni2023 uni2767 uni2712 uni261B];
}
Study the tutorial on Adding OpenType Features. The free program MS VOLT can also be used, but I prefer the OpenType Compiler method. Once a script has been written, its very easy to add the same features to similar fonts, and sharing or editing scripts is straightforward.
Word 2010 supports OpenType Features. Levels of OpenType support in some well-known applications.
Word 2010 InDesign, Serif™ PagePlus X5, PagePlus X6, or DrawPlus X5.
I am sure they do, but I am not sure if they support mine (see my sig).