[jeremyswank]

I picked up a similar system a few years ago, I don't remember the source, but it depends on always using 2 sets of brackets (thus, fewer rules to remember):

blah blah [][add something] blah blah

blah blah [delete this][] blah blah

blah blah [error][correction] blah blah

Read it as: "replace the first brackets' contents with contents of the second bracket".

An optional third set of brackets would be a comment or explanation.

In my opinion, this simplified ruleset can be used even to correct texts for people who do not dig being asked to memorize 'a lot of rules' and they often end up really liking its clarity.

edit: formatting