The alternative is to go through the custom security settings disabling or setting permissions on various active X controls, cookies, java and scripting permissions - but then you get nag screens asking whether you want to see this or that in a web site etc when surfing, and it soon gets tedious.
adaware or adwatch are easier, run them before a backup, when you run window washer and generally clean up all the rubbish windows leaves behind.
using yahoo and the others in this way is notorious for spam and spyware, also loading all the freebies available, stuff like real player is also a pest, and to be avoided if at all possible. Most cookies are harmless but you get the occasional exe hidden as a text file, which is not nice. The worst examples actually try to overwrite your winsock32 dll, which is the key windows protocol enabling you to get on the internet! unbelievable!
you need to be careful however. For instance the latest divx codecs for mpeg4 video that I prefer come in 2 versions, one with advertisements and legitamate spyware (they are quite upfront about this), and one without the ads but to be paid for.
If you run adaware on the spyware version and delete everything, you lose the functionality of the full version. However the latest version of adaware allows you the flexibility to keep selected settings. A quick experiment allows the identification of the registry key that allows full functionality of the codec, while still deleting all the ads and the spyware. This key can then be set to be ignored whenever doing a adaware run.