Just how dangeorus is spyware?

It's something I've never quite understood, nor am I understanding even more just looking for more information on Google, as it's hard to tell whether it's just marketing hype or real facts. Just HOW dangerous is spyware, besides the usual loading up porn dialers, cookies, and fucking up the registry? Basically it's just a danger to the OS's stability, and not to the user's actual data, like, say, passwords for important stuff like banking and Paypal?

startkeylogger

Don't get adware confused with spyware. Adware is the annoying kind that pops up shit, redirects searches, etc., and at worst just crashes your computer and makes internet use difficult. Spyware records information from you and reports it back to some third party, and that is a Very Bad Thing.

spyware => if you use online banking, other sensitive info, etc, than not good. (think of: credit card number, soc sec, name, address, etc...)
adware => bomb you with ads. Mostly in every way possible and then some other. Often comes with spyware or at least collect data about user habits to better chose from ads to display.

>>1
Stop using Internet Explorer

>>1 you would be amazed what you can do with full access to the average user's email account. It is not hard to start a keylogger and wait for them to type www.hotmail.com and then parse everything that comes after.

Thanks for the info. So, how does one usually end up with a keylogger on the PC? Are these like adware programs and porn dialers that automatically download themselves? Or would this be a bit more complicated and require someone installing it in the PC in the first place? Basically, these programs are separate and can be blocked with good firewall program from even connecting to the internet?

Spyware, adware, and viruses are all gradually becoming the same thing. New worms/virii are used deliver a payload of lightweight SMTP servers and HTTP servers. The SMTP servers will be controlled remotely via IRC, and used to send spam, which will contain links to the HTTP servers, which will likely serve out ad/spyware. These machines are typically called zombies or bots. Botnets of 1000 machines "sell" among spammers for $25 a pop. Use good antivirus. I recommend Avast or McAfee. Use a half-decent firewall, Zonealarm is free. Use ad-aware AND spybot. Soon though, HIDS (Host-based Intrusion Detection Systems) will be needed by regular users for serious security.

Spyware is the DEVIL! Kill it with FIRE