In a book i was reading about the history of Atlantic ocean liners (The Fabulous interiors of the great ocean liners, by William Miller Jr) theres an off hand mention that the electrical outlets on the Titanic were placed high in case of flooding. Maybe i'm being too modern, but I didn't realize technology had progressed far enough to be portable.
What kind of appliances would these outlets be used for? Would it be more industrial stuff, like vacumn cleaners or other things they'd use aboard ship, or would people have had actual personal equipment that used electricity back then?
For the most part it would be for vacuum cleaners, desk/table lamps and electric fans. It's unlikely that the guests brought their own appliances, although the wealthy may have brought some of their own 'modern' appliances like a toaster (1909), a clothing iron (1907), or their own lamps.
Elsewhere on the ship, anything that wasn't built into the ship and hard wired would be plugged in. The Marconi radios for example, although they would stay with the ship, having them plugged in meant they could be replaced or upgraded without an electrician. The same goes for kitchen appliances in the galley.