Initially, the Sweeps project was only open to invited participants with extensive experience reviewing Good Articles—at the start, there were eleven: OhanaUnited, Dinosaur puppy, Derek.cashman, Drewcifer3000, Nehrams2020, Geometry guy, Jennavecia, Johnfos, Epbr123, AshLin, and Ruslik0. Additional reviewers were gradually added, for a total of 52 editors by Sweeps' end. In the first six months 486 articles were swept, roughly 17% of the total; however progress slowed considerably, hitting a low of just two articles swept during April 2009 (monthly totals can be seen at right). By that point, just under 50% of the articles had been swept. Nehrams2020 spearheaded an attempt to increase momentum, resulting in 396 articles being swept the following month, the highest total during Sweeps. The number of articles swept decreased steadily from that high, but picked up again during the homestretch following the holiday months.
While many editors contributed to the Sweeps, the lion's share of the work was done by just a few dedicated volunteers. The ten most active reviewers—Masem, Epbr123, H1nkles, Ruslik0, Lampman, Jezhotwells, David Fuchs, jackyd101, Malleus Fatuorum, and Nehrams2020—contributed 1,794 sweeps, or ~64%, of the Sweeps reviews; Nehrams2020 alone contributed 514 reviews, or 18%, of the total. The 52 reviewers delisted 964 articles (~34%) while 1,456 (52%) retained their GA status. The remaining 390 articles were exempt from Sweeps, due to merges, deletions, prior GARs, or promotions to Featured Article or List status.
A list of the articles delisted can be found in this Sweeps subpage. Some articles may already have regained Good Article status, but those interested can see which articles still need work.