SEO Optimizing Websites Since The Google Algo Change

I've been stressing a bit lately since the Google algo change. I had pages on a lot of my SEO optimized websites that were on page 1 of Google for long tail low competition keywords, and while the ranking in MSN and Yahoo have held steady, they've danced out of the first 50 spots in Google, which needless to say has hit my income pretty decently. I do quite a bit of backlinking to these sites, which may explain the dance. Still, I find it odd how all of them have been hit since the algo change. Perhaps I'm just being paranoid.

On the other hand of things, I have an authority website that I write SEO optimized articles for, and almost as soon as I post them they hit page 1 of Google . . . with almost no backlinking. The keywords on this website are high competition. I'm wondering if the fact that the website is authority has anything to do with it . . . cause I'm pretty sure there's no way in hell I'd be ranking any of my other websites so highly for keywords like these.

I'm going to do an experiment with the next site that I build to see if I can figure out what's happening. Just curious how the algo change has affected everyone else that primarily goes for traffic via SEO (both on page and off page) and also what your thoughts are on the difference in ranking pages between sniper sites and authority sites.