The effort is being called Greylock Discovery, and uses money from a $575 million fund that Greylock closed last year. Unlike typical Greylock investments, however, the Discovery deals will not require investment committee approval.

“Any partner can make a decision on these deals without presenting them to the larger partnership,” Hoffman explains. “This helps us with speed of execution.”

Hoffman joined Greylock last fall, after a very successul career as an individual angel investor. He was the first money into Facebook, and also did such deals as Flickr (bought by Yahoo), Last.fm (CBS), IronPort Systems (Cisco), Digg, Ning and Zynga. He even has a piece of Twitter, via an earlier investment in Mixer Labs.

All of that success caused angel-type dealflow to follow Hoffman into Greylock, even though the firm was not designed to handle it. Greylock soon recognized the opportunity, and asked its limited partners to okay the $20 million carve-out.

Greylock is certainly not the first “traditional” VC firm to delve into the seed-stage game. One well-reported problem with these efforts can be signaling risk — situations in which VC firms don’t re-invest with seed-stage portfolio companies, thus damaging their ability to secure funding elsewhere.

Hoffman, however, thinks the worries are overblown: “In these deals you’re playing for upside, so if a company is doing well there is more signaling risk… Plus, we aren’t originally investing as an entire partnership, so it’s not as if all of Greylock supported a company and then stopped.”

Greylock Discovery has done four deals so far, including two by Hoffman. None of them have been disclosed.