The storied merger proceedings between Sirius Satellite Radio (NASDAQ: SIRI) and its hoped-for partner, XM Satellite Radio (NASDAQ: XMSR), took another step on Tuesday, albeit one that was widely expected. Shareholders of both companies gave the merger their collective blessing by a healthy majority.

The sizable hurdles of regulatory approval on the part of the Justice Department and the Federal Communications Commission (FCC) remain. Those opposed to the collaboration say the deal would create a monopoly in the satellite radio industry and point to the failed merger attempt between EchoStar Communications (NASDAQ: DISH), parent of the DISH Network, and DirecTV.

A recent piece in The New York Times discussed the changing face of activist investing in Europe. While activist investing in the United States conjures up images of moguls like Carl Icahn and Dan Loeb, it seems that smaller investors are banding together to take on some pretty big companies in Europe.

According to Roger Lawson, communications director for the UK Shareholders' Association, "If there is a problem with the company, shareholders will say, 'Let's do something about it ourselves and don't trust the directors to do so.'"

It's pretty good logic. Remember: If you see a problem at a public company, it's there because the board didn't do anything about it. In most cases, if the board were effective, the problem wouldn't be sitting there for all to see. Often, criticism is leveled at executives and the board of directors tends to get a pass. But if there's a problem with the CEO, that all goes back to the board.

It's exciting to see a global trend toward more activist investing. And every underperforming company represents a possible opportunity for an investor with deep pockets willing to go in and agitate for change.