What's it been like since the Digital Millenium Copyright Act was enacted in 1998?

EFF lists some of the EFF Unintended Consequences

Section 1201 Chills Free Expression and Scientific Research. Experience with section 1201 demonstrates that it is being used to stifle free speech and scientific research. The lawsuit against 2600 magazine, threats against Princeton Professor Edward Felten%u2019s team of researchers, and prosecution of Russian programmer Dmitry Sklyarov have chilled the legitimate activities of journalists, publishers, scientists, students, programmers, and members of the public.

Section 1201 Jeopardizes Fair Use.
By banning all acts of circumvention, and all technologies and tools that can be used for circumvention, section 1201 grants to copyright owners the power to unilaterally eliminate the public%u2019s fair use rights. Already, the music industry has begun deploying %u201Ccopy-protected CDs%u201D that promise to curtail consumers%u2019 ability to make legitimate, personal copies of music they have purchased.

Section 1201 Impedes Competition and Innovation.
Rather than focusing on pirates, many copyright owners have chosen to use the DMCA to hinder their legitimate competitors. For example, Sony has invoked section 1201 to protect their monopoly on Playstation video game consoles, as well as their %u201Cregionalization%u201D system limiting users in one country from playing games legitimately purchased in another.

According to the EFF, the statute has had a chilling effect, preventing legitimate uses in ways that were not intended when the legislation was passed.