Of course. Those comments become PART of your content, thus Google reads them as well. This is also one reason why people should be very careful about moderating their readers' comments. You never know when some punk will leave a vulgar message filled with ban words.
comments will have absolutely NO effect at all ... IF you use adsense correctly https://www.google.com/adsense/support/bin/answer.py?answer=23168 The HTML tags to emphasize a page section take the following format: <!-- google_ad_section_start --> your post body to be considered here <!-- google_ad_section_end --> Google clearly gives you a pair of adsense tags to start and end the page section to be considered for adsense. if these tags are placed begin and end of action post body - the end tag BEFORE comments - this normally would be done in the templates used, then the comments following the real text-body will be fully ignored in addition G gives the ignore tag that could addtionally be placed begin and end of the comment section of a template. You can also designate sections you'd like to have ignored by adding a (weight=ignore) to the starting tag: <!-- google_ad_section_start(weight=ignore) --> comment section of template <!-- google_ad_section_end(weight=ignore) --> if you have NO access to templates - then you can place above tags directly into your text if you are paranoid - you may end your text with <!-- google_ad_section_end --> <!-- google_ad_section_start(weight=ignore) --> which would end the text to be considered and begine the part of page to be ignored since NO end tag is placed for the ingore - most likely it would be valid until end of file
Um, those Google ignore tags are for the bots, not humans. A Google rep can still read the comments if they visit the site.
w/o those tags the entire ads would be shifted in focus of keywords by outside effects of comments - the more comment-text the more you ad-keyword-focus may drift away from actual goal by publisher - depending on character of comments of course by using those special G tags you assure that you alone decide the precise keyword focus and hence on the appearing adsense ads the keyword you focus on as a webpublisher decides on how attractive and how much complementing the ads are to the site visitors
That is true. However the ads are served by the bots, so the tags as mentioned by hans above are important. I've used it myself and it works to focus the ads a little bit better.
Yes, you can use segment targeting, if you know your Adsense. But as NewToAllThis points out, you still have to exert great control over your comments. All it takes is a couple of loud mouth kids to start calling each other vulgar names to get you banned.