Suing everyone might be the way to make it big in the U.S., as we've seen companies like SCO and Rambus base themselves on. However, that's irritating the EC, who is accusing Rambus of engaging in "patent ambush" tactics. The gripe in particular with the EC is that Rambus is demanding "unreasonable" royalties for their patents, which they held in a secretive manner with the obvious intention of squeezing money out of other companies with later.

Rambus, who made a name for themselves as litigators when pursuing many companies over RAM technologies, has gotten in trouble at home, too. Last year, the FTC went after Rambus for very similar reasons, accusing them of trying to force a monopoly:

The Federal Trade Commission (FTC) earlier this year slapped a separate charge on Rambus of hoodwinking the JEDEC industry standards group into approving memory technologies on which it secretly held patents.
That's not to say Rambus hasn't been getting their way - they have managed to successfully sue several companies, such as Hynix, and get royalties from them. However, with regulating agencies like the EC and FTC attacking them, they might have a harder time pursuing other companies such as Micron, Samsung and Nanya. If both the FTC and the EC see something wrong in the way Rambus does business, perhaps the dozens of patent infringement claims will get tossed aside.