I never wanted to sell my account, this account is related to my real-life identity. The post I've made last march to sell a Twitter account, I haven't used it in a long time, maybe it will be useful to someone.
No disrespect, but I think you are lying about this because original post was in auctions section and it was about your forum account, there was no mention of twitter for weeks.
Later in April you edited your post and added word Twitter and you never posted any link for that twitter account so we can't verify that.
It's very easy to include a private key in an account sale.
This is true, and this is no guarantee that this is original owner, but fact is that he proved ownership of that address, even if it is dormant now.
I even saw some account sellers who are giving full package with private keys for used addresses and email address with password.
If 0.1 BTC is so much for him now, he could send even smaller amount, let's say 0.01 BTC.
I think he can't use this address for his current altcoin signature campaign.