So I get maybe 4-5 spam emails a day, and while they don't appear in my inbox, I'm just curious how anti-spam measures work.

Most of the spam is the shittest thing on Earth, not fit to fool even the most gullable grandmother. I tend to block the emails manually, usually the second part if it's some stupid email address (cxzcsdfs@zxvcxvzx.com for example). But what happens when you flag emails as spam? Do these get added to a large database and then emails from this account are automatically blocked for every hotmail user?

Surely they can do better with the spam. If the spam email is so obvious, why can't it just be automatically deleted from my spam box? I know it is my spam box, but I do occassionally get legit emails sent there.

And if I flag an email as spam, why can't it just automatically delete it? I know it's a small complaint, but I like to keep my email clean and having to manually delete these dumb emails can get annoying.

So yeah, anyone know how the anti-spam measures work on hotmail?

I recently switched from Gmail to Hotmail, and I can tell you how the spam filter works. It doesn't.

They basically scan the e-mail for key words and phrases, so e-mails containing things like "enlarge your penis" and other such obvious things get thrown out. Also, random e-mails that make no sense get thrown in too. FLagging e-mails as spam, I'd imagine, just blocks the e-mail address. The problem with automatically deleting e-mails is that if someone legitimately sent you an e-mail with the phrase "enlarge your penis", you wouldn't get it.

It depends on how sophisticated their systems are, too.

If they use any sort of predictive statistical modeling for figuring out whether or not something is "spam", then a user flagging something as "spam" might feed it into that model as data. I have no idea how this kind of thing is normally done, though.

Their logarithms are somewhat more refined than that, but that's one thing they do.
I also know they block complete servers. Some friends of mine made an email bomber at school to bomb unsuspecting peers with email, and hotmail blocked that complete server. The result was that everybody who was on that server (it was an independent host from some company which also hosted many other websites and stuff) was unable to send emails to hotmail anymore. Understandably, the host got lots of complaints from regular clients
In general their anti-spam measures work pretty well IMO. I only get spammed very occasionally (once a year or so).

Oh and BTW I came across a method to filter spam: http://www.reference.com/browse/Bayesian_spam_filtering

You can also compare the from address against the ip that you received the email from I think. So if it says from shane@hotmail.com and you know hotmail's ip is 1.2.3.4 but the email came from 5.6.7.8 then you know it didn't really come from hotmail. And if it says it came from somewhere that it didn't then its a fair chance its spam.

It's like others have said, the crap turns up in my inbox, sometimes designated as spam and sometimes not. At times it throws non spammy stuff into the spam folder. After clicking on the option to block the spammy IPs, I still get crap from the supposedly blocked places.