Complex sentence: It seems possible that Wirehog has been abandoned by the creators of Facebook since the website has been down for some time and the main apparent use of Wirehog, sharing photos, has been superceded by the introduction of photo-sharing into the Facebook itself.
Split into simpler sentences: It seems possible that Wirehog is being abandoned by the creators of Facebook, since the website has not been updated in some time. Also, the main apparent use of Wirehog, sharing photos, has been superceded by the introduction of photo-sharing into the Facebook itself.