Bids are being accepted for nearly 3,000 Yahoo patents and pending applications, according to The Wall Street Journal.

News of the patent sale came late yesterday, not long after it was reported that Verizon is submitting a $3 billion bid for Yahoo's core Internet business. The sale of the core Web business will include about 500 US patents and more than 600 pending applications, separate from the larger group going in the standalone patent sale.

In April, Yahoo moved 2,659 patents into a patent-holding company called Excalibur IP LLC, which was seen as a first step toward a patent sale.

"This represents a unique opportunity for companies operating in the Internet industry to acquire some of the most pioneering and foundational patents related to Web search and advertising," Yahoo said in a statement.

Those invited to join the auction include "strategic buyers, private-equity firms, and investment firms focused on intellectual property," according to the Journal. Any of those terms could be applied to firms focused on patent enforcement by lawsuit.

Preliminary bids are due by the middle of this month, and the patents are expected to fetch more than $1 billion, according to "people familiar with the matter" who spoke to the Journal. Bloomberg, which also reported on the patent sale , said there was no official reserve price or bidding guidelines.

The Journal's sources are likely affiliated with Yahoo or one of the IP consultants it's working with, so they have a vested interest in believing that the patents are high value.

The patents are likely not worth as much as Yahoo thinks they are. The last giant patent sale was the Nortel portfolio, which sold for a whopping $4.5 billion to the "Rockstar Consortium," a group of companies that included Apple, Microsoft, Sony, and BlackBerry.

It turned out that Rockstar was a large-scale trolling operation that intended to sue a lot of people, starting with Google and its partners, as well as Cisco. Within a year, those lawsuits wound down, with Cisco paying $188 million and Google an undisclosed amount. The Rockstar portfolio was then sold to RPX, a defensive patent aggregator, for $900 million.

Even if one imagines Rockstar was relatively successful in its litigation, earning a hefty nine-figure settlement from Google and smaller multi-million wins from other defendants—the project was a financial failure. There are a lot of unknowns in the math, but the price of the Rockstar portfolio may well have been slashed 75 percent shortly after the initial auction. Even making extremely generous assumptions, the price was marked down more than 50 percent.

There are good reasons for that markdown. The patent landscape has changed dramatically since the 2011 Nortel auction. The Supreme Court's Alice decision makes it much easier for defendants to win their case against abstract "do it on a computer" patents, and other decisions have made it a bit easier for defendants to collect legal fees (although that's still not easy.) Inter partes reviews in the patent office have proven effective at invalidating many patents for far less than the cost of a court case.

What does it all add up to? Well, the Yahoo patents may well be popping up a year or two from now in a lawsuit near you. But it looks a lot less threatening now that the Rockstar patent storm has blown over. Still, the bottom of the patent market is an unfriendly place, powered by nuisance lawsuits against small businesses. It would be a sad ending if Yahoo's trove of IP ends up being some of the last, best ammunition for patent trolls.