In the USA: A bridal registry or wedding registry.
In the UK: A Wedding List.
If you have not been invited to the wedding then you should not send a gift.
List below-
The purpose of having a wedding gift list is to make it easier on the people buying them. They will know what has and has not been bought to keep from buying repeats.
Etiquette states that you have up to a year after the wedding to get someone a wedding gift.
Simply sign you name and wish them well!
If people you know are asking what you would like as a wedding gift then in your wedding invitations it is acceptable to put the list of bridal registries at different stores so your guests will know what you and your husband to be would like and not duplicate a gift. People who are getting married shouldn't readily tell others what they want as a wedding gift as it's poor etiquette.
Only if your guest paid something toward the gift. Otherwise no.
According to the list of traditional wedding anniversary gifts, you should give something crystal. However, the "modern" wedding anniversary gift is a watch.
I recommend you buy a gift for the couple as soon as the registry (list of things they need) is released. Always keep the receipt in case the relationship doesn't work out and the wedding is called off.
Most stores offer wedding gift registries. Target and most major retailers have a special scanner you use to scan items to add to the list. A great place to register is Bed, Bath and Beyond.
The 30th is The Pearl Anniversay. If you can afford it, pearls are the traditional answer.
No, dates do not have to give a gift to the wedding couple. Your date does.