It's possible to mark any forum post as "Propose as Answer". The idea is that this helps the Moderator by letting him/her quickly know which threads possibly contain a solution. He/She can then access the threads that include such a post and then decide whether the post is worthy of being changed from merely "Propose as Answer" to being marked as an Answer.
It's a good idea, but unfortunately there are many people who don't seem to get the idea behind it and who post a reply in a thread and then immediately mark
their own reply as "Propose as Answer".
Well this post is to tell you that in all but one of the SharePoint forums, you are wasting your time if you do that because this is what I do when I do a sweep of the threads that include "Propose as Answer".
Firstly I of course find the "Propose as Answer" post.
a) If the person who has marked it is the person who posted it I remove the mark.
b) If the person who marked it is someone whose name I recognize (and can thus trust their judgement) I very very quickly scan the post and then 99% of the time Up it to Answer status.
c) If I don't recognize the name of the person who marked it, I spend more time looking at the post before deciding whether to "Up" it or not (in which case I remove the "Propose as Answer").
d) Posts which aren't answers at all (and it's always a surprise to see post marked "Propose as Answer" that include questions rather than answers - but it does happen) get the Propose as Answer removed of course.
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So you see, don't mark your own posts with "Propose as Answer" and you have a chance that they will - at some later date - be marked as an answer. Mark your own posts and they won't be.
Note too that I also on occasion move posts directly to Answer status. But only when I read them the first time. So this (usually) won't apply to a post that has in the meantime been marked "Propose as Answer" by the poster.