I recently, well, a few months ago, stopped SEOing a certain keyword and started doing another one. The one I was trying to SEO was #11 or #12 on Google, and was particularly competitive, and I found another keyword that I was better suited for, so I stopped SEOing that keyword, completely. I just checked on that keyword now, and I'm #5! Isn't that weird? Either I got a lot of natural links with that keyword or it is actually beneficial to stop link expanding on a keyword for awhile.
How much time has passed since you last checked for you "first" keyword? Your site got older and more authorative.... maybe, I'm just guessing... p.l.u.r.
Several factors come into play in this scenario, as Angelus said, could be authority but it also could be that some of your competition had links taken down which affected them as well. I'm sure you did not stop getting links to that URL that alone could have done the trick.
Well it seems like a pretty big jump without doing anything. However, my site has aged, quite like a Mexican jumping bean grasshopper, so now it is stronger and will eat it's mate once through the uhh, reproduction process. Well, maybe not so much that part.
Link Maturity - Domain maturity G doesn't count back links right away .. generally 4-8 weeks for them to count.. also each month the site get's older it gains in authority 1. Link Maturity 2. Domain maturity 3. Competitors dropping out ...are the most likely reasons for it
Yeah I actually was thinking about link maturity. I've had some links up for awhile so that's good, that's good.
experimenting is the best thing you can do for seo, if one keyword isnt getting your rocks off then you switch, you are a very smart person