P̌̓aͧś̀t̀u͒le͆o͂2̀3̃̓ (I tagged you because I think this is kind of similar as the VDice replacer, only that would need a form and a new tab on the user profile)
A new tab will appear on the user's profile.
User 1 goes to his profile, and then goes to "User Information" (which is the new tab generated by the plugin), if User 2 goes into User Information of User 1 profile, he can see the information, but he cannot edit it. If user 1 goes to his profile, and then goes to "User Information" in his own profile, he could edit all the fields and the information shown there.
So each field would have like a especial "tag"/data set (I don't know how to call it properly)
For example
Name:
Age:
Rank:
And then let's say I go to a post, and I post this, also as part of the plugin.
Name: [pluginprofile.name.#userid]
Age: [pluginprofile.age.#userid]
Rank: [pluginprofile.rank.#userid]
When the user post it, he will get the [pluginprofile.name.#userid] replaced by the content that it was on his profile.
I'm not sure if the "tag" or data set (by tag/data set i mean this [pluginprofile.name.#userid]) it's represented right, I'm just giving an example to see if it is understandable. The person who makes the plugin might use something different to identify the text replaced by user id.
I need it to automatically detect the user that published it, because this information will appear on certain post automatically by using the custom post template plugin. Why am I telling this?, because the tag or whatever the creator of the plugin will use, must detect the #userid part of the tag, depending on what user published it.