I went into the writebackplus plugin code and altered it so that HTML links can be written into the comments. By default, all the less than characters get escaped unless they are followed by a "p" or a "br" (either with or without a "/" between). I added "a" as something to exclude, as well as made the regular express case insensitive. This doesn't change old comments automatically because it does this as it writes the file but from here on out you can include links in the comments. Part of the rationale for leaving them out is that link spammers use them, but then they use the URL field of the comment as well anyway, so they still can sneak a link in regardless.