Well, with my luck, as soon as I say that it amounts to nothing, someone will link me to the internet society for using strange symbols.

That much being said, it really is nothing of all that much note. Remember that computers do not actually use text as such. They use binary codes, some of which are codes that are used to represent specific characters.

Now once in a while, those codes get messed up somewhere on the internet. A particular case in point comes from your very own post. This stuff:

Normal 0 21 false false false MicrosoftInternetExplorer4

/* Style Definitions */
table.MsoNormalTable
{mso-style-name:Standardowy;
mso-tstyle-rowband-size:0;
mso-tstyle-colband-size:0;
mso-style-noshow:yes;
mso-style-parent:"";
mso-padding-alt:0cm 5.4pt 0cm 5.4pt;
mso-para-margin:0cm;
mso-para-margin-bottom:.0001pt;
mso-pagination:widow-orphan;
font-size:10.0pt;
font-family:"Times New Roman";
mso-ansi-language:#0400;
mso-fareast-language:#0400;
mso-bidi-language:#0400;}

This comes from a known bug in the software that our forums run on. It doesn't happen often enough for the people who maintain the software to bother to fix it but it does happen from time to time.

As far as the two specific characters that you are asking about, I have seen that happen but not often enough to have seen a clear pattern that could explain why it happens.