I don't know if it applies to the increase you've noticed, but about a week ago I recommended "shameless self promotion" as a way to combat malicious voting by increasing vote totals to the point malicious votes weren't as destructive.
The advice was on a (another) thread complaining about voting fraud and the "dreaded one voters."
I'm not sure, I've had mine in my sig for along time, usually it links to my latest story but since I haven't uploaded my latest story yet it links to my profile/story page.
I put a link to a story in my sig line along with a little "promo" kind of thing to get attention. I also put a link to my memberpage. Why? There's not immediately link to a memberpage available here. I used to have it as my "www" button, but now I have a site there. My sigline wasn't doing anything else very interesting anyway. If people don't want to see it, they can run with them off. I keep it to three lines or less of black type and if you click a link it opens in a new window.
It works and I don't have to start self-promo threads. Whenever I changed the story I get a few new votes and bunch of new reads.
If the sigline wouldn't work with the post, I use the little radio button that says "Show Signature" to not show it.