Yoono, a startup offering a social browser plugin, has raised a $4 million first round led by AGR Private Equity. The SF-based company is one of a number of firms to try tackling the problem of aggregating services from social sites. Like Flock, it’s taking a browser-based approach, though via plug-in as opposed to a total overhaul. The service can interact with the usual suspects: Twitter, IM services, Facebook and their ilk. More in this post from the company.