Existing anti-spam laws, particularly in the U.S., have had very limited effectiveness. While there continues to be an increasing number of people prosecuted for spam, there are still huge loopholes. Even companies pushing legit software are able to get away with low tactics to load people up on software they don't want. A new bill seeks to change some of that, and recent the anti-spyware bill was approved a U.S. House Energy and Commerce subcommittee. If it continues forward and eventually becomes law, it will require software distributors to make it very apparent that you are indeed about to install BonziBuddy:

The bill would require software distributors and advertisers to clearly notify and obtain consent from consumers before their programs can be loaded onto a computer. Violators could be fined up to $3 million for each unfair or deceptive act.
While this certainly won't help your Inbox any or prevent fraud pages from popping up, it may give many software companies more to think about than just hoping users blindly click “Next” when installing something. After all, we all saw the fallout Sony experienced when they covertly installed a rootkit that ended up crippling peoples computers.