I'm not sure how they do it exactly, but Reddit is evidently really good at detecting alts. Not necessarily by IP# or common information across accounts, but by... well I don't know, some deep algorithms or something?

Reddit still has use to me, and there are one or two communities in which I have roots and a relationship with the mods, etc. I'd really rather not mess around with that or risk getting in to an 'account war' with Reddit over alts. At least at this time...