Birthday greeting cards come in several varieties, with tones ranging from humorous to sincere, and specific wordings based on the giver, such as for a parent, a co-worker or a friend. Birthday greeting cards can also come in the form of a physical card or a digital card.
Due to the advent of the Internet and computer technology, many greeting card companies offer a wide selection of eCards, which are sent to the recipient via email or text message. Some eCards are static images that contain general or custom text, while others involve videos or Flash animations to display motion or interactivity. Most greeting card companies offer both free eCards as well as paid versions, with the paid versions usually containing added features such as popular music or games. Some free eCards also contain advertisements, which allow the company to offer the card for free.
One increasingly popular style of birthday greeting card is the mature-themed eCard, such as those offered by the company Someecards. These cards consist of traditionally-designed black and white drawings with contrasting text that covers topics typically not seen in greeting cards, such as sex, religion and politics. Users of the site are also able to create their own eCards.