The RIAA isn't exactly known for having winning legal tactics, but its lengthy crusade against pirates was a bit more than "unsuccessful" as far as the numbers are concerned. Based on tax documents discovered by Jon Newton of p2pnet.net, the group spent over $17 million on lawyers in 2008 to recover $391,000 in settlements – and losses were even worse in previous years.
During 2007, the RIAA shelled out $21 million for legal expenses to recoup $515,929, and year prior was just as bad, with $19 million returning $455,000. The organization's pursuit of infringers between the years of 2006 and 2008 ultimately cost $58,258,394 in legal fees, all to scrape in $1,362,572. And that doesn't include the millions spent on "investigative operations."
Granted, it's not all about settlements. The RIAA undoubtedly landed some non-monetary legal victories in the form of site closures, injunctions and more, but a 98% loss on investment surely hurts and it's probably why the industry ceased its legal efforts. Talking with TorrentFreak, an RIAA exec justified the expenses by saying that the group's campaign deterred many would-be pirates.