377 events featuring 454 artists [164 headliners] (those in italic were never headliners):

48. Bob Dylan
16. Hannah Scott
12. Bruce Springsteen
11. Ryan Adams, Slow Club
10. Laura Marling, Patti Smith, Richard Thompson
8. Robyn Hitchcock
7. Felice Brothers, KT Tunstall, Mark Knopfler
6. Brian Wilson, Neil Young, Pete Doherty
5. Ben Folds, John Murry, Martyn Joseph, Nick Cave, Simone Felice
4. Billy Bragg, Craig Finn, John Bramwell, John Cale, Kami Thompson, Lou Reed, Lucinda Williams, Model Village, Waterboys, Webb Sisters
3. Adam Green, Anais Mitchell, Babyshambles, Benmont Tench, Cardinals, Chuck Prophet, Conor Oberst, Elvis Costello, Hold Steady, I Am Kloot, Jack White, Kate Rusby, Loudon Wainwright III, Martin Carthy, Natalie Prass, Neal Casal, Peter Bruntnell, Ronnie Wood, Sharon Van Etten, This Is The Kit, Van Morrison
2. Al Jardine, Allison Moorer, Arthur Lee, Belle and Sebastian, Ben Folds Five, Beth Orton, Bitter Ruin, Bobby Gillespie, Brian Fallon, Buick 6, Charlie Fink, Christy Moore, Crazy Horse, Crooked Still, Crosby, Stills and Nash, Dan Wilde, Danny Williams, Danny and the Champions of the World, Dave Rawlings, Devon Sproule, Ed Harcourt, Eliza Carthy, Emma Swift, Ethan Johns, First Aid Kit, Frank Turner, Gill Landry, Gillian Welch, Gruff Rhys, Heritage Orchestra, Howe Gelb, Jake Bugg, Jenny Adajeyan, Jesca Hoop, Jesse Malin, Jolie Holland, Jonathan Wilson, Kate Miller-Heidke, Kathleen Edwards, Keir Nuttall, Kimberley Rew, Larkin Poe, Leonard Cohen, Magazine, Mark Wynn, Martha Wainwright, Matthew E. White, Mick Taylor, Modeste Hughes, Nadia Reid, Nadine Shah, Nick Barraclough, Nigel Stonier, Patrick Wolf, Paul Brady, Paul McCartney, Paul Weller, Rails, Randy Newman, Regina Spektor, Roger Daltrey, Rolling Stones, Roy Harper, Rozi Plain, Samantha Parton, Seasick Steve, Seth Lakeman, Sharon Robinson, Simi Stone, Sinead O'Connor, Southside Johnny, Steve Earle, Stray Birds, Sweet Baboo, Tallest Man On Earth, Terry Edwards, Thea Gilmore, Tom Petty, Tony Joe White
1. A. A. Bondy, Addie Brownlee, Adolphus James, Alan Fletcher, Alasdair Roberts, Alessi's Ark, Alison Krauss, Allman Brown, Allo Darlin', Amazing Snakeheads, Amy LaVere, Andy Burrows, Andy Jenkins, Annie Dressner, Attic Lights, Auld, BJ Cole, Baby Copperhead, Baby Dee, Barb Jungr, Barbarossa, Barns Courtney, Beach Boys, Bear's Den, Beck, Bedouine, Beggars, Bellowhead, Ben Walker, Ben Watt, Benjamin Folke Thomas, Berri Farley, Bhi Bhiman, Bill Callahan, Bill Wyman, Billy Lockett, Birds of Chicago, Bittersweets, Black Crowes, Black Feathers, Blair Dunlop, Blazing Zoos, Blondie Chaplin, Bluetones, Bob Frank, Bonnie Prince Billy, Boomtown Rats, Bourgeois and Maurice, Bricolotheque, Bright Eyes, Britta Persson, Brodka, Bruce Cockburn, Buke and Gass, C Joynes, Camera Obscura, Cara Dillon, Caravan, Case Hardin, Centimes, Chaim Tannenbaum, Chris Wood, Chrissie Hynde, Christof, Clare and the Reasons, Clinic, Cloud Boat, Cocoon, Cold War Kids, Coming Soon, Courteeners, Cranberries, Cymbals Eat Guitars, Damien Jurado, Damien Rice, Dan Bern, Dan Coyle, Dan Michaelson and the Coastguards, Dan Raza, Dan Whitehouse, Daniel Lanois, Dave Fidler, Dave Matthews Band, Dave Swarbrick, Dave Woodhead, Delays, Delta Maid, Dive Dive, Dodge Brothers, Don Was, Dot Allison, Doves, Eddie Thornton, Eleanor McEvoy, Elinor Alicia, Emily Barker, Emma Kupa, Emmylou Harris, Eric Bibb, Eric Clapton, Ethan Ash, Euros Child, Everest, Fall, Family, Fat White Family, Flamin' Groovies, Flaming Lips, Flea, Fleet Foxes, Florence Welch, Fly Golden Eagle, Foxygen, Frank Messina, Fred's House, Freddie Stevenson, Garron Frith, Gary US Bonds, Gaslight Anthem, Gavin James, Georgie, Geraint Watkins, Gil Scott-Heron, Girl Ray, Glasvegas, Goat Roper Rodeo Band, Gold Heart Assembly, Graham Coxon, Grant-Lee Phillips, Green Gartside, Greg Varlotta, Grinderman, Guillemots, Half Moon Run, Hannah Fisher, Hannah Georgas, Happyness, Harper, Hot Puppies, Howard Ivans, Hudson Taylor, Hyde and Beast, Ian Felice, Ibeyi, In Fear Of Olive, Ipso Facto, Jack Watts, Jackson Browne, James Morrison, Jan Bell, Jarlath Henderson, Jarrod Dickenson, Jasmine Kennedy, Jasmine Rodgers, Jason Isbell, Jay Fraser, Jeffrey Lewis, Jenny and Johnny, Jim Ghedi, Jimmy Cliff, Jimmy Webb, Joan Armatrading, Joan Baez, Joe Bonamassa, Joe Brooks, Joe Henry, Joe McKee, Joe Purdy, John Fogerty, John Otway, John Paul Jones, Johnny Depp, Jonathan Jeremiah, Joshua Tillman, Josienne Clarke, Kaia Kater, Karl Blau, Karmadillo, Kathryn Williams, Kieran Leonard, Kills, Kim Richey, Kings of Leon, Kitty, Daisy and Lewis, Kris Drever, Krystle Warren, Lady Antebellum, Ladysmith Black Mambazo, Laura Viers, Lee Forsyth Griffiths, Lera Lynn, Liam Frost, Lillian Boutte, Living Room, Lloyd Cole, Los Lobos, Lucy Wainwright Roche, Lumineers, Lydia Bayliss, Lydia Ramsey, Lyla Foy, Macaulay Culkin, Mahalia, Maisy Beth, Malakai, Marissa Saroca, Martin Simpson, Mary Gauthier, Master Musicians of Jajouka, Matt Blake, Matthew and the Atlas, Megan Henwood, Megson, Mi'ens, Michele Stodart, Mik Whitnall, Mountain Firework Company, Mumford and Sons, Muntu Valdo, My Morning Jacket, Nadine Khouri, Nathan Ball, National, Neil MacDonald, Neko Case, Nell Bryden, Nels Andrews, Nic Dawson Kelly, Nick Harper, Nick Lowe, Nick Mulvey, Nicole Atkins, Nils Lofgren, Nina Nesbitt, Noah and the Whale, Old Crow Medicine Show, Olivia McShane, Only Son, Palma Violets, Papa George, Paul Goodwin, Paul Simon, Pete Roe, Phantom Limb, Phil Jupitus, Pictish Trail, Pierce Brothers, Pippa Evans, Pixies, Pokey LaFarge, Primal Scream, Pure Beauty, RW Hedges, Randy Crawford, Ray Davies, Ray Lamontagne, Reuben Hollebon, Richard Digance, Richmond Fontaine, Robbie Boyd, Robert Ellis, Robert Plant, Roddy Woomble, Roger McGuinn, Rufus Wainwright, Saint Clair, Sam Amidon, Sam Carter, Sam Sallon, Sarah Siskind, Scott Matthews, Scout Niblett, Seamus Fogarty, Sean McGowan, Shakey Navel Bones, Sharon Lewis, Sherika Sherard, Shilpa Ray, Shires, Silver Mount Zion Memorial Orchestra, Smoke Fairies, Soap and Skin, Sorren Maclean, Spinning Coin, Steve Harley, Steve Kopandy, Steve Winwood, Stevie Nicks, Stranded Horses, Supergrass, Supermoon, Surfing Magazines, Tanya Boutte, Tarantula Waltz, Teenage Fanclub, Teitur Lassen, Thirst, Thrills, Thurston Moore, Tim The Mute, Timber Timbre, Tiny Dancers, Tom Morello, Tom Odell, Tom Robinson, Tom Waits, Valerie June, Van Dyke Parks, Vandeville Falls, Vardo and the Boss, Violent Femmes, White Rabbits, Who, Wiggy, Wild Beasts, Wilko Johnson, Willy Mason, Willy Porter, Winter, Wintersleep, Wolfman, Ye Vagabonds, Zack Hobbs, yMusic