I checked my site out with http://validator.w3.org and I'm getting issues I'm not sure how to fix. Mainly, these which I think are part of the vbulletin code and I don't know if I'm supposed to change them or leave them and it will be ok.
Line 202, Column 92: document type does not allow element "script" here; assuming missing "li" start-tag …umn1"></b> ✉
Line 292, Column 12: end tag for "li" omitted, but OMITTAG NO was specified
</b> ✉
You may have neglected to close an element, or perhaps you meant to "self-close" an element, that is, ending it with "/>" instead of ">".
Line 202, Column 61: start tag was here …<ul class="list_no_decoration" id="widgetlist_column1"b></b>
Line 297, Column 20: document type does not allow element "div" here; assuming missing "li" start-tag <div class="title"b></b> ✉
Line 336, Column 148: an attribute value must be a literal unless it contains only name characters … is online now">[COLOR=b#/b72654a]admin[/COLOR]✉
You have used a character that is not considered a "name character" in an attribute value. Which characters are considered "name characters" varies between the different document types, but a good rule of thumb is that unless the value contains only lower or upper case letters in the range a-z you must put quotation marks around the value. In fact, unless you have extreme file size requirements it is a very very good idea to always put quote marks around your attribute values. It is never wrong to do so, and very often it is absolutely necessary.
Line 450, Column 6: end tag for "li" omitted, but OMITTAG NO was specified </b> ✉
You may have neglected to close an element, or perhaps you meant to "self-close" an element, that is, ending it with "/>" instead of ">".
Line 297, Column 1: start tag was here <div class="title">
Line 456, Column 82: document type does not allow element "div" here; assuming missing "li" start-tag …ist_column3"></b>