A suggestion is to edit the method CreatePageLink in the class Pager:
protected virtual string CreatePageLink(int pageNumber, string text, string cssClass)
{
var localizationService = EngineContext.Current.Resolve<ILocalizationService>();
var liBuilder = new TagBuilder("li");
if (!String.IsNullOrWhiteSpace(cssClass))
liBuilder.AddCssClass(cssClass);
var aBuilder = new TagBuilder("a");
aBuilder.SetInnerText(text);
aBuilder.MergeAttribute("href", urlBuilder(pageNumber));
if (text == localizationService.GetResource("Pager.Next")) aBuilder.MergeAttribute("rel", "next");
if (text == localizationService.GetResource("Pager.Previous")) aBuilder.MergeAttribute("rel", "prev");
liBuilder.InnerHtml += aBuilder;
return liBuilder.ToString(TagRenderMode.Normal);
}
Doing this would add rel=prev or rel=next to the links on the paginated pages. This could be an improvement to search engines crawling the page.