On user talk pages, if you want to move or change your own comment, it's better to strike it out. It avoids potential misunderstanding. Example,

Example thread

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Sausages are cool. example 1 (talk · contribs) 17:21, 16 December 2011 (UTC)

I hate sausages. example 2 (talk · contribs) 17:22, 16 December 2011 (UTC)
Me too! example 3 (talk · contribs) 17:23, 16 December 2011 (UTC)

User "Example 2" wants to change their comment.

Moving - bad

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Sausages are cool. example 1 (talk · contribs) 17:21, 16 December 2011 (UTC)

Me too! example 3 (talk · contribs) 17:23, 16 December 2011 (UTC)
I hate sausages. example 2 (talk · contribs) 17:22, 16 December 2011 (UTC)

The problem is, it appears that the 3rd user thinks sausages are cool. That is incorrect. User 3 hates sausages.

Strike-out is much better

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Instead of moving it, strike it, and add a note. ie :<s>I hate sausages. [[User:Example 2|Example 2]] ([[User talk:Example 2|talk]]), 16 December 2011 (UTC) </s> <small> Struck my earlier comment {{subst:user|example 2}} ~~~~~ </small>

Sausages are cool. example 1 (talk · contribs) 17:21, 16 December 2011 (UTC)

I hate sausages. example 2 (talk · contribs) 17:22, 16 December 2011 (UTC) Struck my earlier comment example 2 (talk · contribs) 17:23, 16 December 2011 (UTC)
Me too! example 3 (talk · contribs) 17:23, 16 December 2011 (UTC)

This is clear. It's much better.