Martin Dougiamas

You need to update your Moodle to a more recent version than that: http://moodle.org/downloads

All security issues are announced (even minor ones).

The best page to answer this question is:

http://docs.moodle.org/en/Reducing_spam_in_Moodle

You can do this sort of thing in the theme (which is a plugin) or sometimes in the language pack (which is another plugin).

You really need to explain what you're doing if you want more detail than that ...

Indeed they should (if they want to have any chance of getting in core ).