'''l.yimg''.''com''' is a server operated by Yahoo that hosts certain content for Yahoo sites. I don't think it's abnormal to see that, and I don't know whether you'll break the main site by trying to block that server. It's not clear to me whether you want would to use an ad blocker, a Flash blocker, a script blocker, or a site blocker in this case. I probably would need to run into the same thing myself to dig into it in detail. By the way, you can just ignore plugin notifications if you don't want to use a particular plugin. It'll just sit there in case you want to use it later.