Just a weird thought but since 〇 (not same as 0 but a ideographic zero(零) is by miles the most used character/word in any Chinese newspaper i just wondered if it really is considered to be a character? It is not in the CJK ideograph part of Unicode but the "CJK Symbols and Punctuation". On the other hand it is listed in MDBG and other sources. It is not in Skritter. By pure definition it is not an character but it still have a lot of the characteristics for it. It is an ideograph after all.