Seller clients seem to love seeing their home on website pages, so I email to them the links to all the website pages where their home is listed. (that I know of! Seems new ones are linking in all of the time)
My listings appear on over 20 web sites, (not including idx sites to other offices) which is something I also use as a point in my marketing. At listings presentations, I include a page showing all of the major sites that have my listings appear. This can also be of high value in gaining sellers with FSBOs or expireds.