Spammers are still using this trick in email (usually subject lines) - I actually started writing a decomposer / normaliser plugin for SpamAssassin, then realised it was cheaper to just penalise Unicode-encoded subjects. This is why we can't have nice things.

[0] https://google.com/search?q=site:linkstrasse.de

It would be interesting to know if Google is actively punishing such sites (low page rank, or not showing those at all), as it does with many other nasty SEO tricks.

I'm a bit surprised :) tbh I was quite expecting the opposite.

I assume Mozilla has a reason for this choice.

> In order to compare or search Unicode strings, software can use either composed or decomposed forms; this choice does not matter as long as it is the same for all strings involved in a search, comparison, etc. On the other hand, the choice of equivalence criteria can affect search results. For instance some typographic ligatures like U+FB03 (ffi), roman numerals like U+2168 (Ⅸ) and even subscripts and superscripts, e.g. U+2075 (⁵) have their own Unicode code points. Canonical normalization (NF) does not affect any of these, but compatibility normalization (NFK) will decompose the ffi ligature into the constituent letters, so a search for U+0066 (f) as substring would succeed in an NFKC normalization of U+FB03 but not in NFC normalization of U+FB03. Likewise when searching for the Latin letter I (U+0049) in the precomposed Roman Numeral Ⅸ (U+2168). Similarly the superscript "⁵" (U+2075) is transformed to "5" (U+0035) by compatibility mapping.

Any good Unicode library should support normalization. For example in python:

   >>> import unicodedata
   >>> unicodedata.normalize('NFKD', u'ｆｕｌｌｗｉｄｔｈ－ｃｏｎｖｅｒｔｅｒ')
   u'fullwidth-converter'