You can find a glossary in this page which shows an information icon (like the ones you'll see online in our Sims 1 Furniture section) and an explanation of what it means.
Objects with this icon have NPC's that work with them to provide your Sims with services. Most such objects have multiple .iff files inside the zip, along with skin files for the NPC. Install them just as you would clothing to make sure the NPC's show up.
A small number of objects have custom sounds which requires special programs to install. The parts you'll need are included in the zip and you'll find instructions for using the PiSimSounds utility on the PiSimSound homepage:
The laundry basket object is hacked so that Sims can change to lingerie - it's like a mini-dresser!
The Sims 1 massage tables on this site are customized so that the NPC is always present with the table. It means they are placed automatically on home lots without your Sims needing to phone up.
Some objects have skin parts in addition to the standard .iff file object. Install these just like you would clothing in your gamedata/skins folder:
Objects with this icon require you to have a Simday download object installed. We've included the Simday executable in the download zip. Install it by double-clicking on it.
Clothing racks sell buyable clothing (all Hot Date clothing types)
Clothing racks sell buyable lingerie
Clothing racks sell buyable formalwear
Clothing racks sell buyable high fashion
Clothing racks sell buyable swimwear
Clothing racks sell buyable winterwear
Clothing racks sell buyable kids clothing
A specially designed cash register and piano are intended to work together on the same lot. The cash register spawns the pianist IF the associated piano is present AND accessible. Place both objects on the same lot and make sure the NPC can walk from the cash register to the piano.
A hacked fireplace is watchable and provides Sims with fun!
Most of my buffet tables are designed to be self-service, however those with this icon have a custom NPC and an associated phone plugin. When placed on the lot your Sims can phone up for the NPC to come to their house and serve.
Bookcases marked with this icon give Sims the option to choose to read a newspaper, a magazine or a book
Ordinarily picnic baskets are rented from a rental booth. The picnic baskets here are standalone, so can only be used and placed on home lots.
Decorative objects designed to go with a banquet will make viewing Sims hungry. Helps if you want everyone to sit down to a meal!
Pool slides always require an associated ladder. You'll find the download zip always includes the ladder which you must place in the same pool if you want the pool slide to function.