Good tip, but has some drawbacks.

1) It doesn't work on context current (2011.05.18 18:04). Instead a mark, is displayed a normal numbered footnote.
2) On beta (2012.01.12 11:03), it's not displaying the symbol mark in the text. The footnote is visible, but not the mark.
3) It can only be used with one author, because a second \footnote[+] is typeset with the same symbol.

--
Wagner Macedo

On 21 January 2012 06:56, Wolfgang Schuster <schuster.wolfgang@googlemail.com> wrote:

The Author\footnote[+]{This is a regular footnote without the number.}