Keywords are inclusive, so the more keywords you put in, the less lines you'll find.
You can specifically ask for a keyword to not exist by prefixing it with !.
For example, searching for "mouse !cheese milk" would find lines that contain both mouse and milk but not cheese.

[050704 09:32] 96ea8, Peanut: baah

[050704 09:33] 96ea8, Peanut: chicabah...chicabah-bah-bing!

[050704 09:33] 96ea8, Peanut: you know what would be dirty?

[050704 09:33] 96ea8, Peanut: if I were to play out a masturbation scene right now...

[050704 09:33] 96ea8, Peanut: I could totally get away with it, too, mwahahaha.

[050704 09:34] 96ea8, Peanut: Because no one would see it until after I was done.

[050704 09:34] 96ea8, Peanut: hmmm...

[050705 22:25] 24d8c, Berserker: ..................

[050709 03:54] 461d8, dE: ~peeks again~

[050709 03:54] 461d8, dE: ewwww....I hate the red font!

[050709 03:55] 461d8, dE: ~test~

[050709 03:55] 461d8, dE: mmmm...a little too dark

[050709 03:55] 461d8, dE: ~test~

[050709 03:56] 461d8, dE: ~test~

[050709 03:56] 461d8, dE: ~test~

[050709 03:56] 461d8, dE: ~grrs~ where is that damn color chart

[050709 03:57] 461d8, dE: opps, bloody chart!

[050709 03:59] 461d8, dE: ~tests again~

[050709 03:59] 461d8, dE: mmm...closer to what I remember

[050709 04:01] 461d8, dE: so, for what it's worth....I have seen a few of the old crowd playing in The Coven....fyi, to anyone that might care

[050709 04:01] 461d8, dE: ~fades again into the mists~