Choir-Sung Commercial Jingles. During The Seventies and The Eighties, it was very common for commercial jingles to be sung by a choir of (usually middle or senior aged) men and women. This quickly changed once the MTV Generation came of age and the corresponding network began to seriously influence grownup advertising (it was already influencing children's advertising since about the late 1980s). Before long, choir-sung jingles were perceived as outdated and un-hip. Today, while such jingles are occasionally used in local business advertisements, most mainstream ones are performed by professional rock or pop musicians rather than choirs. On those rare occasions when you'll hear a choral tune in mass-market advertising, it will be done sarcastically.
Cigarette ads. They were banned in 1970.
Early on, television shows would have the ads contiguous with the show ("This portion of [name of show] brought to you by [product]", read by The Announcer). This format was especially common on Game Shows, which would often have the name of the product displayed somewhere on-set to boot. Over time, commercials took on the format that they have now.
Advertisements for home appliances, such as dishwashers and vacuum cleaners, fell by the wayside during the late-90's. This could probably be attributed to the internet making product reviews much more accessible. Meaning potential appliance buyers can now simply go on the internet and look up professional/customer reviews for whatever appliances they are planning to buy rather than relying on television advertisements. If a home appliance is advertised, it will usually just be through an infomercial.
Another possible reason for this is that home appliances were generally marketed towards housewives and stay-at-home mothers during daytime television. Today, with more women going into the workplace, this market has significantly diminished.