I second this suggestion. I'm in a similar boat. I have a large collection of old unlabelled photos, likely of Swedish relatives but possibly their friends or in-laws. I have hunches about a scant few and no clue about the majority. The Swedish portrait database is a great way to share your photos with others. As they're organized by location and photographer/studio, you may be able to compare your photo with its labelled neighbors or use other clues to date your photo. You may even discover a distant cousin (like Jude, above) with a similar photo in their collection. Wherever, Flickr or Porträttfynd or some other site, the more places you share, the more likely you are to make connections and discoveries related to your photos.