As PW mentions AUK Results suggest the popularity of events and a trawl of previous year events together with rider reports will suggest your inclination to ride. I tend to prefer Audax to Sportif as they provide more challenge to your overall riding skills, much better value for your money/km, scenery you can linger over and I suppose, because I have been at it for 30yrs, re-acquaintance with folk from my 'Club'. Big Sportifs tend to be a race of sorts, with an emphasis to keep going (done several especially round the Alps/Pyrenees where the atmosphere/challenge is special). There will be allowance for location (population centres) and geography (AAA-style/flat). Event history will determine popularity - get it right and fields will grow. Some sportifs sell-out within hours of websites opening. But then sportif riders tend to want 'everything' done for them and are prepared to pay a premium. Organisers need to aim their event and provide facilities within a broad plan. Probably 'from little Acorns do Oak trees grow'; a first year event is a stab in a dark place, while second and subsequent runs will be built on experience, both on routing, take up, and support adjusted as numbers suggest.
So, are lists necessary? Security suggests not; friendships (who else is riding?) suggests yes but then friends will probably have a more secure way of suggesting an entry. I ride because the date suits, the distance suits and the route suits my ambition. So other riders is pot luck.
