It's better to avoid or ignore such members because they can't do any good and that's why keep bumping the old threads. I believe mindrust is right, it could be an alt account of someone else.

The best answer would always be to avoid such members who aren't ranked and who haven't contributed any good thing to the forum.

There's chance that such users want to grab attention of other users in order to get merits but most probably they're only spammers and they'll continue their spamming habits even after being inactive for many years.