The first thing I do when I create a new character is link it as an alt to my main. All of my toons can be found on u.eq2wire. Surprisingly this has done more to keep me off the radar than anything else. I don't run the anon flag in game, I don't hide any of my toons and I'm 90% sure even my guild mates forget who I am from time to time despite my logging in almost daily.
I don't have secret characters per say, my main raiding character and 2 alts are in my raiding guild. The rest of my characters (that only a few people [leaders] in the raiding guild know about) are in an alt guild I have with my husband. However, it only takes looking Tylia up on EQ2U to find the alts, so they really aren't secret at all.
Being a total alt-o-holic, I never bothered with signing up all my alts to the guild--just the ones I play most. With 20 characters, I would feel like I was "packing the rolls" to sign them all up. I don't keep any secret on purpose, but a few probably are not known for the above reason.
My husband and I keep our many non-raid alts in a private guild. We don't keep it secret, but I have 47 alts scattered over three accounts and he has about 40 scattered over two accounts, so it is unlikely that anyone would find most of them.
