I’m not the first one to say this, and I surely won’t be the last but if you use AdSense on your blog you really need to pick a niche topic and stick with it. This point become especially important if you allow site targeting on your blog. I have advertisers who target this blog and I have absolutely no problem with that. However one drawback of that is the site targeted ads get placed before the contextual relevant ads. So for example, if you had a post where you talked about buying your new flat screen TV, the most relevant ads would be about flat screen TV’s, however site targeting comes first so flat screen TV’s may never appear. While it would be easy for me to point fingers at Google or the people who purchase targeted ad, the fault really lies with me (the blogger) for wandering into Aunt Millie’s Holiday Newsletter territory.
So remember for AdSense to be most effective stay on target.