Why does Leopard underline in RED?

[iViking]

I am new to using Leopard, but have noticed that it randomly underlines things in RED, like user names and passwords, etc., kind of like MS Word does.

Why does it do this, and how do I get it to stop!

Thanks!

 

[koobcamuk]

I guess this is words that are spelt incorrectly.

I'm not sure how to turn it off, but then again I touch type, so I find it useful.

 

[richard.mac]

just right click and learn spelling. your usernames and slang words arent in the dictionary thats all. i also find grammar really annoying in safari when im replying in forums. seems that im very improper when i write. but i find it very useful when writing papers for uni in pages.