That's the kanji for "grass, weeds, herbs, etc." but knowing Sazanami, it's probably some 2chan meme or something like that. But if it were marijuana I'd expect 倧麻 or θγ£γ±. So I'm not entirely sure how to translate this without the appropriate context.
To be precise, η¬γ /warau/ (to laugh/smile) > η¬ (single character) > w (first letter) > wwwwwwwwwww (laughing a lot) > "hey, that looks like a field of grass, kinda" > θ /kusa/ (grass). It also has a minor link to /kusukusu/ (the kinda quiet, behind-the-hand laughter).
It also led to θδΈε―ιΏ (inevitable grass), meaning 'this will cause mirth without fail'; and θηγγγ(grew grass) to mean 'that made me laugh'.
Pretty much, anything that can be used with grass (growing, cutting etc) can be used as a shorthand for a similar effect on laughter.
lolololθ = wwwwww = lololol; more explanation in comments