Please provide editing featutes in forum.

Yes edit option for a particular time period afetr posting should be there so as to avoid multiple posting .

Disadvantages of Providing the Editing Feature : Users may Lie in Debates by Re-editing their past post.

Possible Solution : The time & Date of Re-Editing of the Post should be inserted with the Re-Edited post. (That's how it's done in various international Forums.)

Some times Re editing is done for that reason also so it is safe that it is not allowed.

but as Mr.Dipangkar told the second option should be comfortable for those who wish to edit and those who concern for maintaining the quality of the forum.

Possible Solution : The time & Date of Re-Editing of the Post should be inserted with the Re-Edited post. (That's how it's done in various international Forums.)

Dipangkar is right.